diff --git a/src/agent/src/image_rpc.rs b/src/agent/src/image_rpc.rs
index 80952d38f..02a26913a 100644
--- a/src/agent/src/image_rpc.rs
+++ b/src/agent/src/image_rpc.rs
@@ -196,7 +196,7 @@ impl ImageService {
             let v: Vec<&str> = image.rsplit('/').collect();
             if !v[0].is_empty() {
                 // ':' have special meaning for umoci during upack
-                cid = v[0].replace(":", "_");
+                cid = v[0].replace(':', "_");
             } else {
                 return Err(anyhow!("Invalid image name. {}", image));
             }