diff --git a/src/components/Config.tsx b/src/components/Config.tsx
index a0543e9..e254f4f 100644
--- a/src/components/Config.tsx
+++ b/src/components/Config.tsx
@@ -6,24 +6,10 @@ type ConfigProps = {
 };
 
 const RelayConfig = () => {
-  const { config, setConfig } = useConfig();
+  const { config, setConfig, addRelay, removeRelay } = useConfig();
 
   const [relayUrlInput, setRelayUrlInput] = createSignal<string>('');
 
-  const addRelay = (relayUrl: string) => {
-    setConfig((current) => ({
-      ...current,
-      relayUrls: [...current.relayUrls, relayUrl],
-    }));
-  };
-
-  const removeRelay = (relayUrl: string) => {
-    setConfig((current) => ({
-      ...current,
-      relayUrls: current.relayUrls.filter((e) => e !== relayUrl),
-    }));
-  };
-
   const handleClickAddRelay: JSX.EventHandler<HTMLFormElement, Event> = (ev) => {
     ev.preventDefault();
     const relayUrl = ev.currentTarget?.relayUrl?.value as string | undefined;
diff --git a/src/components/NotePostForm.tsx b/src/components/NotePostForm.tsx
index f3fc237..9e8161c 100644
--- a/src/components/NotePostForm.tsx
+++ b/src/components/NotePostForm.tsx
@@ -1,25 +1,75 @@
-import { createSignal, createMemo, onMount, type Component, type JSX } from 'solid-js';
+import { createSignal, createMemo, onMount, For, type Component, type JSX, Show } from 'solid-js';
+import { Event as NostrEvent } from 'nostr-tools';
+
 import PaperAirplane from 'heroicons/24/solid/paper-airplane.svg';
+import XMark from 'heroicons/24/outline/x-mark.svg';
+
+import UserNameDisplay from '@/components/UserDisplayName';
+
+import eventWrapper from '@/core/event';
+
+import useConfig from '@/nostr/useConfig';
+import useCommands from '@/nostr/useCommands';
+import usePubkey from '@/nostr/usePubkey';
 
 type NotePostFormProps = {
-  ref?: HTMLTextAreaElement | undefined;
-  onPost: (textNote: { content: string }) => void;
+  replyTo?: NostrEvent;
+  mode?: 'normal' | 'reply';
   onClose: () => void;
 };
 
-const NotePostForm: Component<NotePostFormProps> = (props) => {
-  const [text, setText] = createSignal<string>('');
+const placeholder = (mode: NotePostFormProps['mode']) => {
+  switch (mode) {
+    case 'normal':
+      return 'いまどうしてる？';
+    case 'reply':
+      return '返信を投稿';
+    default:
+      return 'いまどうしてる？';
+  }
+};
 
+const NotePostForm: Component<NotePostFormProps> = (props) => {
+  let textAreaRef: HTMLTextAreaElement | undefined;
+
+  const { config } = useConfig();
+  const getPubkey = usePubkey();
+  const commands = useCommands();
+
+  const [text, setText] = createSignal<string>('');
   const clearText = () => setText('');
 
+  const replyTo = () => props.replyTo && eventWrapper(props.replyTo);
+  const mode = () => props.mode ?? 'normal';
+  const notifyPubkeys = createMemo(() => replyTo()?.mentionedPubkeys() ?? []);
+
   const handleChangeText: JSX.EventHandler<HTMLTextAreaElement, Event> = (ev) => {
     setText(ev.currentTarget.value);
   };
 
-  // TODO 投稿完了したかどうかの検知をしたい
   const submit = () => {
-    props.onPost({ content: text() });
-    clearText();
+    const pubkey = getPubkey();
+    if (pubkey == null) {
+      console.error('pubkey is not available');
+      return;
+    }
+    commands
+      .publishTextNote({
+        relayUrls: config().relayUrls,
+        pubkey,
+        content: text(),
+        notifyPubkeys: notifyPubkeys(),
+        rootEventId: replyTo()?.rootEvent()?.id ?? replyTo()?.id,
+        replyEventId: replyTo()?.id,
+      })
+      .then(() => {
+        console.log('succeeded to post');
+        clearText();
+        props?.onClose();
+      })
+      .catch((err) => {
+        console.error('error', err);
+      });
   };
 
   const handleSubmit: JSX.EventHandler<HTMLFormElement, Event> = (ev) => {
@@ -37,23 +87,55 @@ const NotePostForm: Component<NotePostFormProps> = (props) => {
 
   const submitDisabled = createMemo(() => text().trim().length === 0);
 
+  onMount(() => {
+    setTimeout(() => {
+      textAreaRef?.focus();
+    }, 50);
+  });
+
   return (
     <div class="p-1">
+      <Show when={notifyPubkeys().length > 0}>
+        <div>
+          <For each={notifyPubkeys()}>
+            {(pubkey) => (
+              <>
+                <UserNameDisplay pubkey={pubkey} />{' '}
+              </>
+            )}
+          </For>
+          に返信
+        </div>
+      </Show>
       <form class="flex flex-col gap-1" onSubmit={handleSubmit}>
         <textarea
-          ref={props.ref}
+          ref={textAreaRef}
           name="text"
           class="rounded border-none"
           rows={4}
-          placeholder="いまどうしてる？"
+          placeholder={placeholder(mode())}
           onInput={handleChangeText}
           onKeyDown={handleKeyDown}
           value={text()}
         />
-        <div class="grid justify-end">
+        <div class="flex items-end justify-end">
+          <Show when={mode() === 'reply'}>
+            <div class="flex-1">
+              <button class="h-5 w-5 text-stone-500" onClick={() => props.onClose()}>
+                <XMark />
+              </button>
+            </div>
+          </Show>
           <button
-            class="h-8 w-8 rounded bg-primary p-2 font-bold text-white"
-            classList={{ 'bg-primary-disabled': submitDisabled(), 'bg-primary': !submitDisabled() }}
+            class="rounded bg-primary p-2 font-bold text-white"
+            classList={{
+              'bg-primary-disabled': submitDisabled(),
+              'bg-primary': !submitDisabled(),
+              'h-8': mode() === 'normal',
+              'w-8': mode() === 'normal',
+              'h-7': mode() === 'reply',
+              'w-7': mode() === 'reply',
+            }}
             type="submit"
             disabled={submitDisabled()}
           >
diff --git a/src/components/ReplyPostForm.tsx b/src/components/ReplyPostForm.tsx
deleted file mode 100644
index ca05bca..0000000
--- a/src/components/ReplyPostForm.tsx
+++ /dev/null
@@ -1,73 +0,0 @@
-import { createSignal, createMemo, type Component, type JSX } from 'solid-js';
-import type { Event as NostrEvent } from 'nostr-tools';
-
-import PaperAirplane from 'heroicons/24/solid/paper-airplane.svg';
-
-type ReplyPostFormProps = {
-  replyTo: NostrEvent;
-  onPost: (textNote: { content: string }) => void;
-  onClose: () => void;
-};
-
-const ReplyPostForm: Component<ReplyPostFormProps> = (props: ReplyPostFormProps) => {
-  const [text, setText] = createSignal<string>('');
-
-  const clearText = () => setText('');
-
-  const handleChangeText: JSX.EventHandler<HTMLTextAreaElement, Event> = (ev) => {
-    setText(ev.currentTarget.value);
-  };
-
-  // TODO 投稿完了したかどうかの検知をしたい
-  const submit = () => {
-    props.onPost({ content: text() });
-    clearText();
-  };
-
-  const handleSubmit: JSX.EventHandler<HTMLFormElement, Event> = (ev) => {
-    ev.preventDefault();
-    submit();
-  };
-
-  const handleKeyDown: JSX.EventHandler<HTMLTextAreaElement, KeyboardEvent> = (ev) => {
-    if (ev.key === 'Enter' && (ev.ctrlKey || ev.metaKey)) {
-      submit();
-    }
-  };
-
-  const submitDisabled = createMemo(() => text().trim().length === 0);
-
-  return (
-    <div class="p-1">
-      <div>
-        {'Replying to '}
-        {props.replyTo.pubkey}
-      </div>
-      <form class="grid w-full gap-1" onSubmit={handleSubmit}>
-        <textarea
-          name="text"
-          class="rounded border-none"
-          rows={4}
-          placeholder="返信を投稿"
-          onInput={handleChangeText}
-          onKeyDown={handleKeyDown}
-          value={text()}
-        />
-        <div class="flex justify-between">
-          {/* TODO あとでちゃんとアイコンにする */}
-          <button onClick={() => props.onClose()}>X</button>
-          <button
-            class="h-7 w-7 rounded bg-primary p-2 font-bold text-white"
-            classList={{ 'bg-primary-disabled': submitDisabled(), 'bg-primary': !submitDisabled() }}
-            type="submit"
-            disabled={submitDisabled()}
-          >
-            <PaperAirplane />
-          </button>
-        </div>
-      </form>
-    </div>
-  );
-};
-
-export default ReplyPostForm;
diff --git a/src/components/SideBar.tsx b/src/components/SideBar.tsx
index e237972..d9731ad 100644
--- a/src/components/SideBar.tsx
+++ b/src/components/SideBar.tsx
@@ -6,56 +6,18 @@ import Cog6Tooth from 'heroicons/24/outline/cog-6-tooth.svg';
 import NotePostForm from '@/components/NotePostForm';
 import Config from '@/components/Config';
 
-import useConfig from '@/nostr/useConfig';
-import useCommands from '@/nostr/useCommands';
-import usePubkey from '@/nostr/usePubkey';
 import { useHandleCommand } from '@/hooks/useCommandBus';
 
 const SideBar: Component = () => {
-  let formTextAreaRef: HTMLTextAreaElement | undefined;
-  const { config } = useConfig();
-  const getPubkey = usePubkey();
-  const commands = useCommands();
-
   const [formOpened, setFormOpened] = createSignal(false);
   const [configOpened, setConfigOpened] = createSignal(false);
 
-  const openForm = () => {
-    setFormOpened(true);
-    setTimeout(() => {
-      formTextAreaRef?.focus?.();
-    }, 100);
-  };
-  const closeForm = () => {
-    setFormOpened(false);
-    formTextAreaRef?.blur?.();
-  };
-
-  const handlePost = ({ content }: { content: string }) => {
-    const pubkey = getPubkey();
-    if (pubkey == null) {
-      console.error('pubkey is not available');
-      return;
-    }
-    commands
-      .publishTextNote({
-        relayUrls: config().relayUrls,
-        pubkey,
-        content,
-      })
-      .then(() => {
-        console.log('succeeded to post');
-      })
-      .catch((err) => {
-        console.error('error', err);
-      });
-  };
+  const openForm = () => setFormOpened(true);
+  const closeForm = () => setFormOpened(false);
 
   useHandleCommand(() => ({
     commandType: 'openPostForm',
-    handler: (cmd) => {
-      openForm();
-    },
+    handler: (cmd) => openForm(),
   }));
 
   return (
@@ -87,7 +49,7 @@ const SideBar: Component = () => {
         </div>
       </div>
       <Show when={formOpened()}>
-        <NotePostForm ref={formTextAreaRef} onPost={handlePost} onClose={closeForm} />
+        <NotePostForm onClose={closeForm} />
       </Show>
       <Show when={configOpened()}>
         <Config onClose={() => setConfigOpened(false)} />
diff --git a/src/components/UserDisplayName.tsx b/src/components/UserDisplayName.tsx
index 4816a83..a1f3f8d 100644
--- a/src/components/UserDisplayName.tsx
+++ b/src/components/UserDisplayName.tsx
@@ -1,4 +1,5 @@
 import { Component, Switch, Match } from 'solid-js';
+import { npubEncode } from 'nostr-tools/nip19';
 
 import useConfig from '@/nostr/useConfig';
 import useProfile from '@/nostr/useProfile';
@@ -15,7 +16,7 @@ const UserNameDisplay: Component<UserNameDisplayProps> = (props) => {
   }));
 
   return (
-    <Switch fallback={`@${props.pubkey}`}>
+    <Switch fallback={npubEncode(props.pubkey)}>
       <Match when={(profile()?.display_name?.length ?? 0) > 0}>{profile()?.display_name}</Match>
       <Match when={(profile()?.name?.length ?? 0) > 0}>@{profile()?.name}</Match>
     </Switch>
diff --git a/src/components/notification/Reaction.tsx b/src/components/notification/Reaction.tsx
index 235d7da..f1afed9 100644
--- a/src/components/notification/Reaction.tsx
+++ b/src/components/notification/Reaction.tsx
@@ -9,6 +9,7 @@ import UserDisplayName from '@/components/UserDisplayName';
 import useConfig from '@/nostr/useConfig';
 import useProfile from '@/nostr/useProfile';
 import useEvent from '@/nostr/useEvent';
+import { npubEncode } from 'nostr-tools/nip19';
 
 type ReactionProps = {
   event: NostrEvent;
@@ -63,10 +64,11 @@ const Reaction: Component<ReactionProps> = (props) => {
         </div>
         <div class="notification-event py-1">
           <Show
-            when={reactedEvent() != null}
+            when={reactedEvent()}
             fallback={<div class="truncate">loading {eventId()}</div>}
+            keyed
           >
-            <TextNoteDisplay event={reactedEvent()} />
+            {(event) => <TextNoteDisplay event={event} />}
           </Show>
         </div>
       </ColumnItem>
diff --git a/src/components/textNote/GeneralUserMentionDisplay.tsx b/src/components/textNote/GeneralUserMentionDisplay.tsx
index bc7cecb..b339d29 100644
--- a/src/components/textNote/GeneralUserMentionDisplay.tsx
+++ b/src/components/textNote/GeneralUserMentionDisplay.tsx
@@ -1,7 +1,8 @@
-import type { MentionedUser } from '@/core/parseTextNote';
+import { Show } from 'solid-js';
+import { npubEncode } from 'nostr-tools/nip19';
+
 import useProfile from '@/nostr/useProfile';
 import useConfig from '@/nostr/useConfig';
-import { Show } from 'solid-js';
 
 export type GeneralUserMentionDisplayProps = {
   pubkey: string;
@@ -15,7 +16,7 @@ const GeneralUserMentionDisplay = (props: GeneralUserMentionDisplayProps) => {
   }));
 
   return (
-    <Show when={(profile()?.name?.length ?? 0) > 0} fallback={`@${props.pubkey}`}>
+    <Show when={(profile()?.name?.length ?? 0) > 0} fallback={`@${npubEncode(props.pubkey)}`}>
       @{profile()?.name ?? props.pubkey}
     </Show>
   );
diff --git a/src/components/textNote/ImageDisplay.tsx b/src/components/textNote/ImageDisplay.tsx
index 7e9449d..5f17b7b 100644
--- a/src/components/textNote/ImageDisplay.tsx
+++ b/src/components/textNote/ImageDisplay.tsx
@@ -1,29 +1,13 @@
-import { Component, createSignal, Show } from 'solid-js';
-import { ContentWarning } from '@/core/event';
+import { Component, createEffect, createSignal, Show } from 'solid-js';
+import { fixUrl } from '@/utils/imageUrl';
 
 type ImageDisplayProps = {
   url: string;
-  contentWarning: ContentWarning;
-};
-
-const fixUrl = (url: URL): string => {
-  const result = new URL(url);
-  if (url.host === 'i.imgur.com') {
-    const match = url.pathname.match(/^\/([a-zA-Z0-9]+)\.(jpg|jpeg|png|gif)/);
-    if (match != null) {
-      const imageId = match[1];
-      result.pathname = `${imageId}l.webp`;
-    }
-  } else if (url.host === 'i.gyazo.com') {
-    result.host = 'thumb.gyazo.com';
-    result.pathname = `/thumb/640_w${url.pathname}`;
-  }
-  return result.toString();
+  initialHidden: boolean;
 };
 
 const ImageDisplay: Component<ImageDisplayProps> = (props) => {
-  const [hidden, setHidden] = createSignal(props.contentWarning.contentWarning);
-  const url = () => new URL(props.url);
+  const [hidden, setHidden] = createSignal(props.initialHidden);
 
   return (
     <Show
@@ -40,7 +24,7 @@ const ImageDisplay: Component<ImageDisplayProps> = (props) => {
       <a class="my-2 block" href={props.url} target="_blank" rel="noopener noreferrer">
         <img
           class="inline-block max-h-64 max-w-full rounded object-contain shadow hover:shadow-md"
-          src={fixUrl(url())}
+          src={fixUrl(new URL(props.url)).toString()}
           alt={props.url}
         />
       </a>
diff --git a/src/components/textNote/TextNoteContentDisplay.tsx b/src/components/textNote/TextNoteContentDisplay.tsx
index 3e05d9c..cdaadf5 100644
--- a/src/components/textNote/TextNoteContentDisplay.tsx
+++ b/src/components/textNote/TextNoteContentDisplay.tsx
@@ -1,4 +1,4 @@
-import { For, Switch, Match } from 'solid-js';
+import { For } from 'solid-js';
 import parseTextNote, { type ParsedTextNoteNode } from '@/core/parseTextNote';
 import type { Event as NostrEvent } from 'nostr-tools';
 import PlainTextDisplay from '@/components/textNote/PlainTextDisplay';
@@ -6,6 +6,7 @@ import MentionedUserDisplay from '@/components/textNote/MentionedUserDisplay';
 import MentionedEventDisplay from '@/components/textNote/MentionedEventDisplay';
 import ImageDisplay from '@/components/textNote/ImageDisplay';
 import eventWrapper from '@/core/event';
+import { isImageUrl } from '@/utils/imageUrl';
 import EventLink from '../EventLink';
 import TextNoteDisplayById from './TextNoteDisplayById';
 
@@ -45,8 +46,13 @@ const TextNoteContentDisplay = (props: TextNoteContentDisplayProps) => {
           return <span class="text-blue-500 underline">{item.content}</span>;
         }
         if (item.type === 'URL') {
-          if (item.content.match(/\.(jpeg|jpg|png|gif|webp)$/i) && props.embedding) {
-            return <ImageDisplay url={item.content} contentWarning={event().contentWarning()} />;
+          if (isImageUrl(new URL(item.content))) {
+            return (
+              <ImageDisplay
+                url={item.content}
+                initialHidden={event().contentWarning().contentWarning || !props.embedding}
+              />
+            );
           }
           return (
             <a
diff --git a/src/components/textNote/TextNoteDisplay.tsx b/src/components/textNote/TextNoteDisplay.tsx
index 8cc7bca..b448246 100644
--- a/src/components/textNote/TextNoteDisplay.tsx
+++ b/src/components/textNote/TextNoteDisplay.tsx
@@ -1,4 +1,13 @@
-import { Show, For, createSignal, createMemo, type JSX, type Component } from 'solid-js';
+import {
+  Show,
+  For,
+  createSignal,
+  createMemo,
+  type JSX,
+  type Component,
+  Match,
+  Switch,
+} from 'solid-js';
 import type { Event as NostrEvent } from 'nostr-tools';
 
 import HeartOutlined from 'heroicons/24/outline/heart.svg';
@@ -9,8 +18,9 @@ import EllipsisHorizontal from 'heroicons/24/outline/ellipsis-horizontal.svg';
 
 import ColumnItem from '@/components/ColumnItem';
 import GeneralUserMentionDisplay from '@/components/textNote/GeneralUserMentionDisplay';
+import ContentWarningDisplay from '@/components/textNote/ContentWarningDisplay';
 import TextNoteContentDisplay from '@/components/textNote/TextNoteContentDisplay';
-import ReplyPostForm from '@/components/ReplyPostForm';
+import NotePostForm from '@/components/NotePostForm';
 
 import eventWrapper from '@/core/event';
 
@@ -24,7 +34,9 @@ import useDeprecatedReposts from '@/nostr/useDeprecatedReposts';
 import useFormatDate from '@/hooks/useFormatDate';
 
 import ensureNonNull from '@/utils/ensureNonNull';
-import ContentWarningDisplay from './ContentWarningDisplay';
+import { npubEncode } from 'nostr-tools/nip19';
+import UserNameDisplay from '../UserDisplayName';
+import TextNoteDisplayById from './TextNoteDisplayById';
 
 export type TextNoteDisplayProps = {
   event: NostrEvent;
@@ -32,15 +44,15 @@ export type TextNoteDisplayProps = {
   actions?: boolean;
 };
 
-const ContentWarning = (props) => {};
-
 const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
   const { config } = useConfig();
   const formatDate = useFormatDate();
   const commands = useCommands();
   const pubkey = usePubkey();
+
   const [showReplyForm, setShowReplyForm] = createSignal(false);
-  const [showContentWarning, setShowContentWarning] = createSignal(false);
+  const [postingRepost, setPostingRepost] = createSignal(false);
+  const [postingReaction, setPostingReaction] = createSignal(false);
 
   const event = createMemo(() => eventWrapper(props.event));
 
@@ -54,41 +66,41 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
 
   const { reactions, isReactedBy, invalidateReactions } = useReactions(() => ({
     relayUrls: config().relayUrls,
-    eventId: props.event.id,
+    eventId: props.event.id as string, // TODO いつかなおす
   }));
 
   const { reposts, isRepostedBy, invalidateDeprecatedReposts } = useDeprecatedReposts(() => ({
     relayUrls: config().relayUrls,
-    eventId: props.event.id,
+    eventId: props.event.id as string, // TODO いつかなおす
   }));
 
   const isReactedByMe = createMemo(() => isReactedBy(pubkey()));
   const isRepostedByMe = createMemo(() => isRepostedBy(pubkey()));
 
-  const createdAt = () => formatDate(event().createdAtAsDate());
-
-  const handleReplyPost = ({ content }: { content: string }) => {
-    commands
-      .publishTextNote({
-        relayUrls: config().relayUrls,
-        pubkey: pubkey(),
-        content,
-        notifyPubkeys: [event().pubkey, ...event().mentionedPubkeys()],
-        rootEventId: event().rootEvent()?.id ?? props.event.id,
-        replyEventId: props.event.id,
-      })
-      .then(() => {
-        setShowReplyForm(false);
-      });
+  const showReplyEvent = (): string | undefined => {
+    const replyingToEvent = event().replyingToEvent();
+    if (
+      embedding() &&
+      replyingToEvent != null &&
+      !event().containsEventMentionIndex(replyingToEvent.index)
+    ) {
+      return replyingToEvent.id;
+    }
+    return undefined;
   };
 
+  const createdAt = () => formatDate(event().createdAtAsDate());
+
   const handleRepost: JSX.EventHandler<HTMLButtonElement, MouseEvent> = (ev) => {
     if (isRepostedByMe()) {
       // TODO remove reaction
       return;
     }
-    ev.preventDefault();
+    if (postingRepost()) {
+      return;
+    }
 
+    setPostingRepost(true);
     ensureNonNull([pubkey(), props.event.id] as const)(([pubkeyNonNull, eventIdNonNull]) => {
       commands
         .publishDeprecatedRepost({
@@ -98,7 +110,8 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
           notifyPubkey: props.event.pubkey,
         })
         .then(() => invalidateDeprecatedReposts())
-        .catch((err) => console.error('failed to repost: ', err));
+        .catch((err) => console.error('failed to repost: ', err))
+        .finally(() => setPostingRepost(false));
     });
   };
 
@@ -107,8 +120,11 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
       // TODO remove reaction
       return;
     }
-    ev.preventDefault();
+    if (postingReaction()) {
+      return;
+    }
 
+    setPostingReaction(true);
     ensureNonNull([pubkey(), props.event.id] as const)(([pubkeyNonNull, eventIdNonNull]) => {
       commands
         .publishReaction({
@@ -119,7 +135,8 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
           notifyPubkey: props.event.pubkey,
         })
         .then(() => invalidateReactions())
-        .catch((err) => console.error('failed to publish reaction: ', err));
+        .catch((err) => console.error('failed to publish reaction: ', err))
+        .finally(() => setPostingReaction(false));
     });
   };
 
@@ -145,23 +162,31 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
                 <div class="author-name truncate pr-1 font-bold">{author()?.display_name}</div>
               </Show>
               <div class="author-username truncate text-zinc-600">
-                <Show when={author()?.name} fallback={props.event.pubkey}>
+                <Show when={author()?.name != null} fallback={`@${npubEncode(props.event.pubkey)}`}>
                   @{author()?.name}
                 </Show>
+                {/* TODO <Match when={author()?.nip05 != null}>@{author()?.nip05}</Match> */}
               </div>
             </div>
             <div class="created-at shrink-0">{createdAt()}</div>
           </div>
-          <Show when={event().mentionedPubkeys().length > 0}>
+          <Show when={showReplyEvent()} keyed>
+            {(id) => (
+              <div class="rounded border p-1">
+                <TextNoteDisplayById eventId={id} actions={false} embedding={false} />
+              </div>
+            )}
+          </Show>
+          <Show when={event().mentionedPubkeysWithoutAuthor().length > 0}>
             <div class="text-xs">
-              {'Replying to '}
-              <For each={event().mentionedPubkeys()}>
+              <For each={event().mentionedPubkeysWithoutAuthor()}>
                 {(replyToPubkey: string) => (
                   <span class="pr-1 text-blue-500 underline">
                     <GeneralUserMentionDisplay pubkey={replyToPubkey} />
                   </span>
                 )}
               </For>
+              {'への返信'}
             </div>
           </Show>
           <ContentWarningDisplay contentWarning={event().contentWarning()}>
@@ -184,7 +209,7 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
                   'text-green-400': isRepostedByMe(),
                 }}
               >
-                <button class="h-4 w-4" onClick={handleRepost}>
+                <button class="h-4 w-4" onClick={handleRepost} disabled={postingRepost()}>
                   <ArrowPathRoundedSquare />
                 </button>
                 <Show when={reposts().length > 0}>
@@ -198,7 +223,7 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
                   'text-rose-400': isReactedByMe(),
                 }}
               >
-                <button class="h-4 w-4" onClick={handleReaction}>
+                <button class="h-4 w-4" onClick={handleReaction} disabled={postingReaction()}>
                   <Show when={isReactedByMe()} fallback={<HeartOutlined />}>
                     <HeartSolid />
                   </Show>
@@ -215,11 +240,7 @@ const TextNoteDisplay: Component<TextNoteDisplayProps> = (props) => {
         </div>
       </div>
       <Show when={showReplyForm()}>
-        <ReplyPostForm
-          replyTo={props.event}
-          onPost={handleReplyPost}
-          onClose={() => setShowReplyForm(false)}
-        />
+        <NotePostForm mode="reply" replyTo={props.event} onClose={() => setShowReplyForm(false)} />
       </Show>
     </div>
   );
diff --git a/src/core/event.ts b/src/core/event.ts
index 6e53261..1ce5aaf 100644
--- a/src/core/event.ts
+++ b/src/core/event.ts
@@ -6,6 +6,7 @@ export type EventMarker = 'reply' | 'root' | 'mention';
 export type TaggedEvent = {
   id: string;
   relayUrl?: string;
+  index: number;
   marker: EventMarker;
 };
 
@@ -28,8 +29,8 @@ const eventWrapper = (event: NostrEvent) => {
     get createdAt(): number {
       return event.created_at;
     },
-    get content(): Date {
-      return new Date(event.created_at * 1000);
+    get content(): string {
+      return event.content;
     },
     createdAtAsDate(): Date {
       return new Date(event.created_at * 1000);
@@ -44,7 +45,9 @@ const eventWrapper = (event: NostrEvent) => {
       return Array.from(pubkeys);
     },
     taggedEvents(): TaggedEvent[] {
-      const events = event.tags.filter(([tagName]) => tagName === 'e');
+      const events = event.tags
+        .map((tag, originalIndex) => [tag, originalIndex] as const)
+        .filter(([[tagName]]) => tagName === 'e');
 
       // NIP-10: Positional "e" tags (DEPRECATED)
       const positionToMarker = (index: number): EventMarker => {
@@ -61,10 +64,11 @@ const eventWrapper = (event: NostrEvent) => {
         return 'mention';
       };
 
-      return events.map(([, eventId, relayUrl, marker], index) => ({
+      return events.map(([[, eventId, relayUrl, marker], originalIndex], eTagIndex) => ({
         id: eventId,
         relayUrl,
-        marker: (marker as EventMarker | undefined) ?? positionToMarker(index),
+        marker: (marker as EventMarker | undefined) ?? positionToMarker(eTagIndex),
+        index: originalIndex,
       }));
     },
     replyingToEvent(): TaggedEvent | undefined {
@@ -79,6 +83,9 @@ const eventWrapper = (event: NostrEvent) => {
     mentionedPubkeys(): string[] {
       return uniq(event.tags.filter(([tagName]) => tagName === 'p').map((e) => e[1]));
     },
+    mentionedPubkeysWithoutAuthor(): string[] {
+      return this.mentionedPubkeys().filter((pubkey) => pubkey !== event.pubkey);
+    },
     contentWarning(): ContentWarning {
       const tag = event.tags.find(([tagName]) => tagName === 'content-warning');
       if (tag == null) return { contentWarning: false };
@@ -86,6 +93,15 @@ const eventWrapper = (event: NostrEvent) => {
       const reason = (tag[1]?.length ?? 0) > 0 ? tag[1] : undefined;
       return { contentWarning: true, reason };
     },
+    containsEventMention(eventId: string): boolean {
+      const tagIndex = event.tags.findIndex(([tagName, id]) => tagName === 'e' && id === eventId);
+      if (tagIndex < 0) return false;
+      return this.containsEventMentionIndex(tagIndex);
+    },
+    containsEventMentionIndex(index: number): boolean {
+      if (index < 0 || index >= event.tags.length) return false;
+      return event.content.includes(`#[${index}]`);
+    },
   };
 };
 
diff --git a/src/core/parseTextNote.ts b/src/core/parseTextNote.ts
index 5179f90..d2e3b6b 100644
--- a/src/core/parseTextNote.ts
+++ b/src/core/parseTextNote.ts
@@ -55,7 +55,7 @@ export type ParsedTextNote = ParsedTextNoteNode[];
 export const parseTextNote = (event: NostrEvent): ParsedTextNote => {
   const matches = [
     ...event.content.matchAll(/(?:#\[(?<idx>\d+)\])/g),
-    ...event.content.matchAll(/#(?<hashtag>[^[-`:-@!-/{-~\d\s][^[-`:-@!-/{-~\s]+)/g),
+    ...event.content.matchAll(/#(?<hashtag>[^[-^`:-@!-/{-~\d\s][^[-^`:-@!-/{-~\s]+)/g),
     ...event.content.matchAll(
       /(?<nip19>(npub|note|nprofile|nevent|nrelay|naddr)1[ac-hj-np-z02-9]+)/gi,
     ),
diff --git a/src/hooks/useFileInput.ts b/src/hooks/useFileInput.ts
new file mode 100644
index 0000000..1e6ee6a
--- /dev/null
+++ b/src/hooks/useFileInput.ts
@@ -0,0 +1,11 @@
+import { createSignal, type JSX } from 'solid-js';
+
+const useFileInput = () => {
+  const [file, setFile] = createSignal<File | undefined>();
+
+  const handleChange: JSX.EventHandler<HTMLInputElement, Event> = (ev) => {
+    setFile(ev.currentTarget.files?.[0]);
+  };
+
+  return { file, handleChange };
+};
diff --git a/src/hooks/useFormatDate.ts b/src/hooks/useFormatDate.ts
index 13a8b27..b886aad 100644
--- a/src/hooks/useFormatDate.ts
+++ b/src/hooks/useFormatDate.ts
@@ -1,20 +1,24 @@
-import { createMemo } from 'solid-js';
-
 import useConfig from '@/nostr/useConfig';
 
 import useDatePulser from '@/hooks/useDatePulser';
 
-import { formatRelative, formatAbsolute } from '@/utils/formatDate';
+import { formatRelative, formatAbsoluteLong, formatAbsoluteShort } from '@/utils/formatDate';
 
 const useFormatDate = () => {
   const { config } = useConfig();
   const currentDate = useDatePulser();
 
   return (date: Date) => {
-    if (config().dateFormat === 'absolute') {
-      return formatAbsolute(date);
+    switch (config().dateFormat) {
+      case 'absolute-long':
+        return formatAbsoluteLong(date, currentDate());
+      case 'absolute-short':
+        return formatAbsoluteShort(date, currentDate());
+      case 'relative':
+        return formatRelative(date, currentDate());
+      default:
+        return formatRelative(date, currentDate());
     }
-    return formatRelative(date, currentDate());
   };
 };
 
diff --git a/src/nostr/useBatchedEvents.ts b/src/nostr/useBatchedEvents.ts
index eb0aedb..ab615d8 100644
--- a/src/nostr/useBatchedEvents.ts
+++ b/src/nostr/useBatchedEvents.ts
@@ -1,4 +1,4 @@
-import { createSignal, createMemo, type Signal, type Accessor } from 'solid-js';
+import { createSignal, createMemo, createRoot, type Signal, type Accessor } from 'solid-js';
 import { type Event as NostrEvent, type Filter } from 'nostr-tools';
 
 import useConfig from '@/nostr/useConfig';
@@ -50,9 +50,11 @@ const useBatchedEvents = <TaskArgs>(propsProvider: () => UseBatchedEventsProps<T
       const getSignalForKey = (key: string | number): Signal<BatchedEvents> => {
         const eventsSignal =
           keyEventSignalsMap.get(key) ??
-          createSignal<BatchedEvents>({
-            events: [],
-            completed: false,
+          createRoot((dispose) => {
+            return createSignal<BatchedEvents>({
+              events: [],
+              completed: false,
+            });
           });
         keyEventSignalsMap.set(key, eventsSignal);
         return eventsSignal;
diff --git a/src/nostr/useConfig.ts b/src/nostr/useConfig.ts
index 03938f3..c66b9e5 100644
--- a/src/nostr/useConfig.ts
+++ b/src/nostr/useConfig.ts
@@ -6,12 +6,14 @@ import {
 
 type Config = {
   relayUrls: string[];
-  dateFormat: 'relative' | 'absolute';
+  dateFormat: 'relative' | 'absolute-long' | 'absolute-short';
 };
 
 type UseConfig = {
   config: Accessor<Config>;
   setConfig: Setter<Config>;
+  addRelay: (url: string) => void;
+  removeRelay: (url: string) => void;
 };
 
 const InitialConfig: Config = {
@@ -37,7 +39,21 @@ const storage = createStorageWithSerializer(() => window.localStorage, serialize
 const [config, setConfig] = createSignalWithStorage('RabbitConfig', InitialConfig, storage);
 
 const useConfig = (): UseConfig => {
-  return { config, setConfig };
+  const addRelay = (relayUrl: string) => {
+    setConfig((current) => ({
+      ...current,
+      relayUrls: [...current.relayUrls, relayUrl],
+    }));
+  };
+
+  const removeRelay = (relayUrl: string) => {
+    setConfig((current) => ({
+      ...current,
+      relayUrls: current.relayUrls.filter((e) => e !== relayUrl),
+    }));
+  };
+
+  return { config, setConfig, addRelay, removeRelay };
 };
 
 export default useConfig;
diff --git a/src/nostr/useSubscription.ts b/src/nostr/useSubscription.ts
index 66300ec..fb6e225 100644
--- a/src/nostr/useSubscription.ts
+++ b/src/nostr/useSubscription.ts
@@ -8,6 +8,7 @@ export type UseSubscriptionProps = {
   options?: SubscriptionOptions;
   // subscribe not only stored events but also new events published after the subscription
   // default is true
+  clientEventFilter?: (event: NostrEvent) => boolean;
   continuous?: boolean;
   onEvent?: (event: NostrEvent) => void;
   onEOSE?: () => void;
@@ -36,6 +37,9 @@ const useSubscription = (propsProvider: () => UseSubscriptionProps | null) => {
       if (onEvent != null) {
         onEvent(event);
       }
+      if (props.clientEventFilter != null && !props.clientEventFilter(event)) {
+        return;
+      }
       if (!eose) {
         pushed = true;
         storedEvents.push(event);
diff --git a/src/nostr/useThread.ts b/src/nostr/useThread.ts
new file mode 100644
index 0000000..50174ca
--- /dev/null
+++ b/src/nostr/useThread.ts
@@ -0,0 +1,7 @@
+const filter = {
+  kinds: [1],
+  '#e': [
+    rootEventId,
+    currentEventId,
+  ],
+};
diff --git a/src/pages/Hello.tsx b/src/pages/Hello.tsx
index 8f1a4ef..6b6c50a 100644
--- a/src/pages/Hello.tsx
+++ b/src/pages/Hello.tsx
@@ -62,7 +62,7 @@ const Hello: Component = () => {
           </Match>
           <Match when={signerStatus() === 'unavailable'}>
             <div class="pb-1 text-lg font-bold">拡張機能がインストールされていません！</div>
-            <p>
+            <p class="pt-2">
               利用にはNIP-07に対応した拡張機能が必要です。
               <br />
               <a
@@ -73,7 +73,19 @@ const Hello: Component = () => {
               >
                 こちらを参考
               </a>
-              に拡張機能をインストールしてください
+              に拡張機能をインストールしてください。
+            </p>
+            <p class="pt-2">
+              はじめてNostrを利用する方は
+              <a
+                class="text-blue-500 underline"
+                target="_blank"
+                rel="noopener noreferrer"
+                href="https://scrapbox.io/nostr/%E3%81%AF%E3%81%98%E3%82%81%E3%81%A6%E3%81%AENostr%E3%80%90%E3%81%AF%E3%81%98%E3%82%81%E3%81%A6%E3%81%AE%E6%96%B9%E3%81%AF%E3%81%93%E3%81%A1%E3%82%89%E3%80%91"
+              >
+                はじめてのNostr
+              </a>
+              を参考にするとよいでしょう。
             </p>
           </Match>
           <Match when={signerStatus() === 'available'}>
diff --git a/src/utils/file.ts b/src/utils/file.ts
new file mode 100644
index 0000000..2630763
--- /dev/null
+++ b/src/utils/file.ts
@@ -0,0 +1,19 @@
+const readAs =
+  <T>(fn: (reader: FileReader, file: File) => void) =>
+  (file: File): Promise<T | undefined> =>
+    new Promise<T | undefined>((resolve) => {
+      const reader = new FileReader();
+      reader.addEventListener('load', () => {
+        // user must specify correct type
+        resolve(reader.result as T);
+      });
+      fn(reader, file);
+    });
+
+export const dataUrl = readAs<string>((reader, file) => {
+  reader.readAsDataURL(file);
+});
+
+export const arrayBuffer = readAs<ArrayBuffer>((reader, file) => {
+  reader.readAsArrayBuffer(file);
+});
diff --git a/src/utils/formatDate.ts b/src/utils/formatDate.ts
index a4986c7..a90fbec 100644
--- a/src/utils/formatDate.ts
+++ b/src/utils/formatDate.ts
@@ -1,4 +1,4 @@
-type ParsedDate =
+export type RelativeDate =
   | { kind: 'now' }
   | { kind: 'seconds'; value: number }
   | { kind: 'minutes'; value: number }
@@ -6,9 +6,15 @@ type ParsedDate =
   | { kind: 'days'; value: number }
   | { kind: 'abs'; value: Date };
 
-export type DateFormatter = (parsedDate: ParsedDate) => string;
+export type AbsoluteDate =
+  | { kind: 'today'; value: Date }
+  | { kind: 'yesterday'; value: Date }
+  | { kind: 'abs'; value: Date };
 
-const defaultDateFormatter = (parsedDate: ParsedDate): string => {
+export type RelativeDateFormatter = (parsedDate: RelativeDate) => string;
+export type AbsoluteDateFormatter = (parsedDate: AbsoluteDate) => string;
+
+const defaultRelativeDateFormatter = (parsedDate: RelativeDate): string => {
   switch (parsedDate.kind) {
     case 'now':
       return 'now';
@@ -21,16 +27,41 @@ const defaultDateFormatter = (parsedDate: ParsedDate): string => {
     case 'days':
       return `${parsedDate.value}d`;
     case 'abs':
-      return parsedDate.value.toLocaleDateString();
     default:
-      return '';
+      return parsedDate.value.toLocaleDateString();
+  }
+};
+
+const formatTime = (date: Date): string =>
+  `${date.getHours()}:${date.getMinutes().toString().padStart(2, '0')}`;
+
+const defaultAbsoluteDateLongFormatter = (parsedDate: AbsoluteDate): string => {
+  switch (parsedDate.kind) {
+    case 'today':
+      return parsedDate.value.toLocaleTimeString();
+    case 'yesterday':
+    case 'abs':
+    default:
+      return parsedDate.value.toLocaleDateString();
+  }
+};
+
+const defaultAbsoluteDateShortFormatter = (parsedDate: AbsoluteDate): string => {
+  switch (parsedDate.kind) {
+    case 'today':
+      return formatTime(parsedDate.value);
+    case 'yesterday':
+      return `昨日 ${formatTime(parsedDate.value)}`;
+    case 'abs':
+    default:
+      return parsedDate.value.toLocaleString();
   }
 };
 
 const calcDiffSec = (date: Date, currentDate: Date): number =>
   (Number(currentDate) - Number(date)) / 1000;
 
-const parseDateDiff = (date: Date, currentDate: Date): ParsedDate => {
+const parseDateDiff = (date: Date, currentDate: Date): RelativeDate => {
   const diffSec = calcDiffSec(date, currentDate);
 
   if (diffSec < 10) {
@@ -53,19 +84,35 @@ const parseDateDiff = (date: Date, currentDate: Date): ParsedDate => {
   return { kind: 'abs', value: date };
 };
 
-export const formatAbsolute = (date: Date, currentDate: Date = new Date()): string => {
-  if (
-    date.getFullYear() === currentDate.getFullYear() &&
-    date.getMonth() === currentDate.getMonth() &&
-    date.getDate() === currentDate.getDate()
-  ) {
-    return date.toLocaleTimeString();
+const isSameDate = (lhs: Date, rhs: Date): boolean =>
+  lhs.getFullYear() === rhs.getFullYear() &&
+  lhs.getMonth() === rhs.getMonth() &&
+  lhs.getDate() === rhs.getDate();
+
+const yesterdayOf = (date: Date): Date => new Date(+date - 24 * 60 * 60 * 1000);
+
+const formatAbsolute = (
+  date: Date,
+  currentDate: Date,
+  formatter: AbsoluteDateFormatter,
+): string => {
+  if (isSameDate(date, currentDate)) {
+    return formatter({ kind: 'today', value: date });
   }
-  return date.toLocaleString();
+  if (isSameDate(date, yesterdayOf(currentDate))) {
+    return formatter({ kind: 'yesterday', value: date });
+  }
+  return formatter({ kind: 'abs', value: date });
 };
 
+export const formatAbsoluteLong = (date: Date, currentDate: Date = new Date()) =>
+  formatAbsolute(date, currentDate, defaultAbsoluteDateLongFormatter);
+
+export const formatAbsoluteShort = (date: Date, currentDate: Date = new Date()) =>
+  formatAbsolute(date, currentDate, defaultAbsoluteDateShortFormatter);
+
 export const formatRelative = (
   date: Date,
   currentDate: Date = new Date(),
-  formatter: DateFormatter = defaultDateFormatter,
+  formatter: RelativeDateFormatter = defaultRelativeDateFormatter,
 ): string => formatter(parseDateDiff(date, currentDate));
diff --git a/src/utils/imageUpload.ts b/src/utils/imageUpload.ts
new file mode 100644
index 0000000..9fd3e5d
--- /dev/null
+++ b/src/utils/imageUpload.ts
@@ -0,0 +1,32 @@
+const toHexString = (buff: ArrayBuffer): string => {
+  const arr = new Array(buff.byteLength);
+  const view = new Int8Array(buff);
+
+  for (let i = 0; i < view.byteLength; i += 1) {
+    arr[i] = view[i].toString(16).padStart(2, '0');
+  }
+
+  return arr.join();
+};
+
+const upload = async (blob: Blob): Promise<object> => {
+  const data = await blob.arrayBuffer();
+  const digestBuffer = await window.crypto.subtle.digest('SHA-256', data);
+  const digest = toHexString(digestBuffer);
+
+  const res = await fetch('https://void.cat/upload', {
+    method: 'POST',
+    headers: {
+      'V-Content-Type': blob.type,
+      'V-Full-Digest': digest,
+    },
+    mode: 'cors',
+    body: data,
+  });
+
+  if (!res.ok) throw new Error('failed to post image: status code was not 2xx');
+
+  return res.json();
+};
+
+export default upload;
diff --git a/src/utils/imageUrl.ts b/src/utils/imageUrl.ts
new file mode 100644
index 0000000..a569ddf
--- /dev/null
+++ b/src/utils/imageUrl.ts
@@ -0,0 +1,33 @@
+const domains = ['i.imgur.com', 'imgur.com', 'i.gyazo.com'];
+
+export const isImageUrl = (url: URL): boolean => {
+  if (url.pathname.match(/\.(jpeg|jpg|png|gif|webp)$/i)) return true;
+  if (domains.includes(url.host)) return true;
+
+  return false;
+};
+
+export const fixUrl = (url: URL): URL => {
+  // Imgur
+  if (url.host === 'i.imgur.com' || url.host === 'imgur.com') {
+    const match = url.pathname.match(/^\/([a-zA-Z0-9]+)\.(jpg|jpeg|png|gif)/);
+    if (match != null) {
+      const result = new URL(url);
+      const imageId = match[1];
+      result.host = 'i.imgur.com';
+      result.pathname = `${imageId}l.webp`;
+      return result;
+    }
+    return url;
+  }
+
+  // Gyazo
+  if (url.host === 'i.gyazo.com') {
+    const result = new URL(url);
+    result.host = 'thumb.gyazo.com';
+    result.pathname = `/thumb/640_w${url.pathname}`;
+    return result;
+  }
+
+  return url;
+};