diff --git a/src/components/Post.tsx b/src/components/Post.tsx
index b271fe6..62fd859 100644
--- a/src/components/Post.tsx
+++ b/src/components/Post.tsx
@@ -46,7 +46,12 @@ const Post: Component<PostProps> = (props) => {
             {(url) => (
               <LazyLoad>
                 {() => (
-                  <img src={thumbnailUrl(url)} alt="icon" class="h-full w-full object-cover" />
+                  <img
+                    src={thumbnailUrl(url, 'icon')}
+                    alt="icon"
+                    referrerpolicy="no-referrer"
+                    class="h-full w-full object-cover"
+                  />
                 )}
               </LazyLoad>
             )}
diff --git a/src/components/event/Reaction.tsx b/src/components/event/Reaction.tsx
index 311ea24..6d1172c 100644
--- a/src/components/event/Reaction.tsx
+++ b/src/components/event/Reaction.tsx
@@ -51,7 +51,7 @@ const ReactionDisplay: Component<ReactionDisplayProps> = (props) => {
             <Show when={profile()?.picture} keyed>
               {(url) => (
                 <img
-                  src={thumbnailUrl(url)}
+                  src={thumbnailUrl(url, 'icon')}
                   alt="icon"
                   // TODO autofit
                   class="h-full w-full object-cover"
diff --git a/src/components/event/ZapReceipt.tsx b/src/components/event/ZapReceipt.tsx
index 0163429..0cc68d7 100644
--- a/src/components/event/ZapReceipt.tsx
+++ b/src/components/event/ZapReceipt.tsx
@@ -15,6 +15,7 @@ import lud06ToLnurlPayUrl from '@/nostr/zap/lud06ToLnurlPayUrl';
 import lud16ToLnurlPayUrl from '@/nostr/zap/lud16ToLnurlPayUrl';
 import ensureNonNull from '@/utils/ensureNonNull';
 import { formatSiPrefix } from '@/utils/siPrefix';
+import { thumbnailUrl } from '@/utils/url';
 
 export type ZapReceiptProps = {
   event: NostrEvent;
@@ -82,7 +83,7 @@ const ZapReceiptDisplay: Component<ZapReceiptProps> = (props) => {
           <div class="author-icon h-5 w-5 shrink-0 overflow-hidden rounded">
             <Show when={senderProfile()?.picture != null}>
               <img
-                src={senderProfile()?.picture}
+                src={thumbnailUrl(senderProfile()?.picture, 'icon')}
                 alt="icon"
                 // TODO autofit
                 class="h-full w-full object-cover"
diff --git a/src/utils/url.test.ts b/src/utils/url.test.ts
index defe98b..31f8e25 100644
--- a/src/utils/url.test.ts
+++ b/src/utils/url.test.ts
@@ -5,9 +5,15 @@ import { describe, it } from 'vitest';
 import { thumbnailUrl } from '@/utils/url';
 
 describe('thumbnailUrl', () => {
-  it('should return an image url for a given imgur.com URL with additional path', () => {
-    const actual = thumbnailUrl('https://imgur.com/uBf5Qts.jpeg');
-    const expected = 'https://i.imgur.com/uBf5Qtsl.webp';
+  it('should return thumbnail url for imgur.com', () => {
+    const actual = thumbnailUrl('https://i.imgur.com/p05kUim.gif');
+    const expected = 'https://i.imgur.com/p05kUiml.gif';
+    assert.deepStrictEqual(actual, expected);
+  });
+
+  it('should return thumbnail url for imgur.com', () => {
+    const actual = thumbnailUrl('https://i.imgur.com/p05kUim.gif', 'icon');
+    const expected = 'https://i.imgur.com/p05kUims.gif';
     assert.deepStrictEqual(actual, expected);
   });
 
@@ -16,25 +22,41 @@ describe('thumbnailUrl', () => {
       'https://nostr.build/i/2489ee648a4fef6943f4a7c88349477e78a91e28232246b801fe8ce86e64624e.png',
     );
     const expected =
-      'https://nostr.build/responsive/240p/i/2489ee648a4fef6943f4a7c88349477e78a91e28232246b801fe8ce86e64624e.png';
+      'https://image.nostr.build/resp/240p/2489ee648a4fef6943f4a7c88349477e78a91e28232246b801fe8ce86e64624e.png';
     assert.deepStrictEqual(actual, expected);
   });
 
   it('should return url for image.nostr.build', () => {
     const actual = thumbnailUrl(
-      'https://image.nostr.build/f56ee902307158c1ebbcb5ac00430dbf1425eac12d55e4277ebccbe54d09671b.jpg',
+      'https://image.nostr.build/78fc3c02f0488e2f3efb818adf1421bcee8c1612189e217c5ced1c2785eee1a8.jpg',
     );
     const expected =
-      'https://nostr.build/responsive/240p/i/f56ee902307158c1ebbcb5ac00430dbf1425eac12d55e4277ebccbe54d09671b.jpg';
+      'https://image.nostr.build/resp/240p/78fc3c02f0488e2f3efb818adf1421bcee8c1612189e217c5ced1c2785eee1a8.jpg';
     assert.deepStrictEqual(actual, expected);
   });
 
   it('should return url for cdn.nostr.build', () => {
     const actual = thumbnailUrl(
-      'https://cdn.nostr.build/i/6a2868ebb53da2c295e3a2a20a29fa009f230f721b71e88c7ffc3ec8eaae870f.png',
+      'https://cdn.nostr.build/i/78fc3c02f0488e2f3efb818adf1421bcee8c1612189e217c5ced1c2785eee1a8.jpg',
     );
     const expected =
-      'https://nostr.build/responsive/240p/i/6a2868ebb53da2c295e3a2a20a29fa009f230f721b71e88c7ffc3ec8eaae870f.png';
+      'https://image.nostr.build/resp/240p/78fc3c02f0488e2f3efb818adf1421bcee8c1612189e217c5ced1c2785eee1a8.jpg';
+    assert.deepStrictEqual(actual, expected);
+  });
+
+  it('should return url for pbs.twimg.com/profile_images/', () => {
+    const actual = thumbnailUrl(
+      'https://pbs.twimg.com/profile_images/1713367977725509632/iLgoXgtx_400x400.jpg',
+    );
+    const expected = 'https://pbs.twimg.com/profile_images/1713367977725509632/iLgoXgtx_normal.jpg';
+    assert.deepStrictEqual(actual, expected);
+  });
+
+  it('should return url for pbs.twimg.com/media/', () => {
+    const actual = thumbnailUrl(
+      'https://pbs.twimg.com/media/FPUltrpaAAQQdIO?format=png&name=900x900',
+    );
+    const expected = 'https://pbs.twimg.com/media/FPUltrpaAAQQdIO?format=jpg&name=small';
     assert.deepStrictEqual(actual, expected);
   });
 });
diff --git a/src/utils/url.ts b/src/utils/url.ts
index de0040d..0233ba9 100644
--- a/src/utils/url.ts
+++ b/src/utils/url.ts
@@ -28,7 +28,10 @@ export const isWebSocketUrl = (urlString: string): boolean => {
 /**
  * Generate a URL of thumbnail for a given URL.
  */
-export const thumbnailUrl = (urlString: string): string => {
+export const thumbnailUrl = (
+  urlString: string,
+  size: 'icon' | 'thumbnail' = 'thumbnail',
+): string => {
   try {
     const url = new URL(urlString);
     // Imgur
@@ -37,8 +40,16 @@ export const thumbnailUrl = (urlString: string): string => {
       if (match != null) {
         const result = new URL(url);
         const imageId = match[1];
+        const ext = match[2];
         result.host = 'i.imgur.com';
-        result.pathname = `${imageId}l.webp`;
+        if (size === 'icon') {
+          result.pathname = `${imageId}s.${ext}`;
+        } else if (size === 'thumbnail') {
+          result.pathname = `${imageId}l.${ext}`;
+        } else {
+          // fallback
+          return urlString;
+        }
         return result.toString();
       }
       return url.toString();
@@ -48,32 +59,80 @@ export const thumbnailUrl = (urlString: string): string => {
     if (url.host === 'i.gyazo.com') {
       const result = new URL(url);
       result.host = 'thumb.gyazo.com';
-      result.pathname = `/thumb/640${url.pathname}`;
-      return result.toString();
-    }
-
-    // nostr.build
-    // https://github.com/nostrbuild/nostr.build/blob/main/api/v2/routes_upload.php
-    if (
-      url.host === 'nostr.build' ||
-      url.host === 'image.nostr.build' ||
-      url.host === 'cdn.nostr.build'
-    ) {
-      const result = new URL(url);
-      result.host = 'nostr.build';
-      // profile pic (PFP)
-      if (url.pathname.startsWith('/i/p/')) return urlString;
-
-      if (url.pathname.startsWith('/i/')) {
-        result.pathname = `/responsive/240p${url.pathname}`;
-      } else if (url.pathname.match(/^\/[0-9a-zA-Z]+\.(jpeg|jpg|png|gif|webp|avif|apng)$/)) {
-        result.pathname = `/responsive/240p/i${url.pathname}`;
+      if (size === 'icon') {
+        result.pathname = `/thumb/160${url.pathname}`;
+      } else if (size === 'thumbnail') {
+        result.pathname = `/thumb/640${url.pathname}`;
       } else {
+        // fallback
         return urlString;
       }
       return result.toString();
     }
 
+    // nostr.build
+    // https://github.com/nostrbuild/nostr.build/blob/main/SiteConfig.php#L71-L75
+    // https://github.com/nostrbuild/nostr.build/blob/main/api/v2/routes_upload.php
+    if (
+      url.host === 'nostr.build' ||
+      url.host === 'i.nostr.build' ||
+      url.host === 'image.nostr.build' ||
+      url.host === 'cdn.nostr.build'
+    ) {
+      // profile pic (PFP)
+      if (url.pathname.startsWith('/i/p/')) return urlString;
+
+      const result = new URL(url);
+      if (url.pathname.startsWith('/i/')) {
+        const withoutI = url.pathname.replace(/^\/i/, '');
+        result.hostname = 'image.nostr.build';
+        result.pathname = `/resp/240p${withoutI}`;
+      } else if (url.pathname.match(/^\/[0-9a-zA-Z]+\.(jpeg|jpg|png|gif|webp|avif|apng)$/)) {
+        result.pathname = `/resp/240p${url.pathname}`;
+      } else {
+        // fallback
+        return urlString;
+      }
+      return result.toString();
+    }
+
+    // pbs.twimg.com
+    // https://qiita.com/ma7ma7pipipi/items/713460b24710e0a46242
+    if (url.host === 'pbs.twimg.com') {
+      if (url.pathname.startsWith('/profile_images/')) {
+        const result = new URL(url);
+        result.pathname = url.pathname.replace(
+          /(?:_(?:mini|normal|bigger|200x200|400x400))?\.(jpg|png)$/,
+          '_normal.$1',
+        );
+        return result.toString();
+      }
+      if (url.pathname.startsWith('/media/')) {
+        const result = new URL(url);
+        result.searchParams.set('format', 'jpg');
+        result.searchParams.set('name', 'small');
+        return result.toString();
+      }
+      return urlString;
+    }
+
+    // media.discrodapp.net
+    if (
+      url.hostname === 'media.discordapp.net' &&
+      url.pathname.match(/^\/attachments\/\d+\/\d+\/[a-z0-9]+\.(png|jpg|gif)/)
+    ) {
+      const result = new URL(url);
+      result.searchParams.set('format', 'webp');
+      if (size === 'icon') {
+        result.searchParams.set('width', '100');
+        result.searchParams.set('height', '100');
+      } else if (size === 'thumbnail') {
+        result.searchParams.set('width', '320');
+        result.searchParams.set('height', '320');
+      } else {
+        return urlString;
+      }
+    }
     return url.toString();
   } catch {
     return urlString;