diff --git a/src/channels/feishu.rs b/src/channels/feishu.rs
index ed6c4a2..651d7a5 100644
--- a/src/channels/feishu.rs
+++ b/src/channels/feishu.rs
@@ -356,14 +356,28 @@ impl FeishuChannel {
             return Err(ChannelError::Other(format!("Image download failed {}: {}", status, error_text)));
         }
 
+        let content_type = resp
+            .headers()
+            .get("content-type")
+            .and_then(|v| v.to_str().ok())
+            .unwrap_or("image/jpeg");
+
+        let ext = match content_type {
+            "image/png" => "png",
+            "image/gif" => "gif",
+            "image/webp" => "webp",
+            "image/bmp" => "bmp",
+            _ => "jpg",
+        };
+
         let data = resp.bytes().await
             .map_err(|e| ChannelError::Other(format!("Failed to read image data: {}", e)))?
             .to_vec();
 
         #[cfg(debug_assertions)]
-        tracing::debug!(data_len = %data.len(), "Downloaded image data");
+        tracing::debug!(data_len = %data.len(), content_type = %content_type, "Downloaded image data");
 
-        let filename = format!("{}_{}.jpg", message_id, &image_key[..8.min(image_key.len())]);
+        let filename = format!("{}_{}.{}", message_id, &image_key[..8.min(image_key.len())], ext);
         let file_path = media_dir.join(&filename);
 
         tokio::fs::write(&file_path, &data).await