fix: hold gif thumbnails until first frame is ready

Distinguish GIF frame loading from GIF frame failure in useFetchGifFirstFrame(), so thread and catalog thumbnails no longer render animated GIFs before the still frame arrives. Keep the existing animated fallback when the first-frame fetch actually fails.

src/components/catalog-row/catalog-row.tsx

@@ -35,7 +35,7 @@ interface CatalogPostMediaProps {
 export const CatalogPostMedia = ({ cid, commentMediaInfo, linkWidth, linkHeight }: CatalogPostMediaProps) => {
   const { patternThumbnailUrl, thumbnail, type, url } = commentMediaInfo || {};
   const iframeThumbnail = patternThumbnailUrl || thumbnail;
-  const gifFrameUrl = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
+  const { frameUrl: gifFrameUrl, status: gifFrameStatus } = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
   const [isLoaded, setIsLoaded] = useState(false);
   const [hasError, setHasError] = useState(false);
   const handleLoad = () => setIsLoaded(true);
@@ -76,8 +76,10 @@ export const CatalogPostMedia = ({ cid, commentMediaInfo, linkWidth, linkHeight
 
   let thumbnailComponent: React.ReactNode = null;
 
-  if (type === 'gif' && gifFrameUrl && !hasError) {
+  if (type === 'gif' && gifFrameStatus === 'ready' && gifFrameUrl && !hasError) {
     thumbnailComponent = <img src={gifFrameUrl} alt='' onLoad={handleLoad} onError={handleError} style={loadingStyle} width={numericWidth} height={numericHeight} />;
+  } else if (type === 'gif' && gifFrameStatus === 'failed' && !hasError) {
+    thumbnailComponent = <img src={url} alt='' onLoad={handleLoad} onError={handleError} style={loadingStyle} width={numericWidth} height={numericHeight} />;
   } else if (type === 'image' && !hasError) {
     thumbnailComponent = <img src={url} alt='' onLoad={handleLoad} onError={handleError} style={loadingStyle} width={numericWidth} height={numericHeight} />;
   } else if (type === 'video' && !hasError) {

src/components/comment-media/comment-media.module.css

@@ -11,7 +11,8 @@
   overflow: hidden;
 }
 
-.floatingEmbed, .subplebbitAvatar {
+.floatingEmbed,
+.subplebbitAvatar {
   max-width: 250px;
   max-height: 250px;
   display: inline-flex;
@@ -53,7 +54,8 @@
   overflow: hidden;
 }
 
-.thumbnailSmall span, .thumbnailSmall a {
+.thumbnailSmall span,
+.thumbnailSmall a {
   width: 100%;
   display: inline-block;
   word-wrap: break-word;
@@ -81,7 +83,10 @@
   display: block;
 }
 
-.content img, .content video, .content iframe, .content audio {
+.content img,
+.content video,
+.content iframe,
+.content audio {
   max-width: 100%;
   max-height: 100%;
   object-fit: contain;
@@ -91,6 +96,13 @@
   cursor: pointer;
 }
 
+.gifPlaceholder {
+  width: 100%;
+  height: 100%;
+  display: inline-block;
+  cursor: pointer;
+}
+
 .content iframe {
   border: none;
   color-scheme: light;
@@ -125,11 +137,17 @@
   margin: 8px 10px 5px 5px;
 }
 
-.mediaMobile img, .mediaMobile video, .mediaMobile iframe, .mediaMobile audio {
+.mediaMobile img,
+.mediaMobile video,
+.mediaMobile iframe,
+.mediaMobile audio {
   padding: 3px 0 5px 0;
 }
 
-.mediaDesktopReply img, .mediaDesktopReply video, .mediaDesktopReply iframe, .mediaDesktopReply audio {
+.mediaDesktopReply img,
+.mediaDesktopReply video,
+.mediaDesktopReply iframe,
+.mediaDesktopReply audio {
   padding: 3px 20px 5px 20px;
 }
 
@@ -138,7 +156,10 @@
   box-sizing: border-box;
 }
 
-.mediaDesktopOp img, .mediaDesktopOp video, .mediaDesktopOp iframe, .mediaDesktopOp audio {
+.mediaDesktopOp img,
+.mediaDesktopOp video,
+.mediaDesktopOp iframe,
+.mediaDesktopOp audio {
   padding: 3px 20px 5px 20px;
   max-width: 100%;
   box-sizing: border-box;

src/components/comment-media/comment-media.tsx

@@ -45,25 +45,42 @@ const Thumbnail = ({
 
   let thumbnailComponent: React.ReactNode = null;
   const iframeThumbnail = patternThumbnailUrl || thumbnail;
-  const gifFrameUrl = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
+  const { frameUrl: gifFrameUrl, status: gifFrameStatus } = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
   const hasThumbnail = getHasThumbnail(commentMediaInfo, url);
+  const gifThumbnailButtonProps =
+    gifFrameStatus === 'loading'
+      ? {
+          role: 'button' as const,
+          tabIndex: 0,
+          onKeyDown: (e: React.KeyboardEvent<HTMLSpanElement>) => {
+            if (e.key === 'Enter' || e.key === ' ') {
+              e.preventDefault();
+              setShowThumbnail(false);
+            }
+          },
+          onClick: () => setShowThumbnail(false),
+        }
+      : {};
 
   if (type === 'gif') {
-    thumbnailComponent = (
-      <img
-        src={gifFrameUrl || url}
-        alt=''
-        role='button'
-        tabIndex={0}
-        onKeyDown={(e) => {
-          if (e.key === 'Enter' || e.key === ' ') {
-            e.preventDefault();
-            setShowThumbnail(false);
-          }
-        }}
-        onClick={() => setShowThumbnail(false)}
-      />
-    );
+    thumbnailComponent =
+      gifFrameStatus === 'loading' ? (
+        <span className={styles.gifPlaceholder} aria-label='Loading GIF thumbnail' {...gifThumbnailButtonProps} />
+      ) : (
+        <img
+          src={gifFrameUrl || url}
+          alt=''
+          role='button'
+          tabIndex={0}
+          onKeyDown={(e) => {
+            if (e.key === 'Enter' || e.key === ' ') {
+              e.preventDefault();
+              setShowThumbnail(false);
+            }
+          }}
+          onClick={() => setShowThumbnail(false)}
+        />
+      );
   } else if (type === 'video') {
     thumbnailComponent = thumbnail ? (
       <img src={thumbnail} alt='' />
@@ -405,11 +422,11 @@ const CommentMedia = ({
   const isMobile = useIsMobile();
   const { thumbnailHeight, thumbnailWidth, url } = commentMediaInfo || {};
   let type = commentMediaInfo?.type;
-  const gifFrameUrl = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
+  const { status: gifFrameStatus } = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
 
-  if (type === 'gif' && gifFrameUrl) {
+  if (type === 'gif' && gifFrameStatus === 'ready') {
     type = 'animated gif';
-  } else if (type === 'gif' && !gifFrameUrl) {
+  } else if (type === 'gif' && gifFrameStatus === 'failed') {
     type = 'static gif';
   }
 

src/components/post-desktop/post-desktop.tsx

@@ -590,12 +590,12 @@ const PostMedia = ({
   const { t } = useTranslation();
   const { url } = commentMediaInfo || {};
   let type = commentMediaInfo?.type;
-  const gifFrameUrl = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
+  const { status: gifFrameStatus } = useFetchGifFirstFrame(type === 'gif' ? url : undefined);
   const directories = useDirectories();
 
-  if (type === 'gif' && gifFrameUrl !== null) {
+  if (type === 'gif' && gifFrameStatus === 'ready') {
     type = 'animated gif';
-  } else if (type === 'gif' && gifFrameUrl === null) {
+  } else if (type === 'gif' && gifFrameStatus === 'failed') {
     type = 'static gif';
   }
 

src/components/post-form/post-form.tsx

@@ -39,11 +39,11 @@ export const LinkTypePreviewer = ({ link }: { link: string }) => {
   const { t } = useTranslation();
   const mediaInfo = getLinkMediaInfo(link);
   let type = mediaInfo?.type;
-  const gifFrameUrl = useFetchGifFirstFrame(type === 'gif' ? mediaInfo?.url : undefined);
+  const { status: gifFrameStatus } = useFetchGifFirstFrame(type === 'gif' ? mediaInfo?.url : undefined);
 
-  if (type === 'gif' && gifFrameUrl !== null) {
+  if (type === 'gif' && gifFrameStatus === 'ready') {
     type = t('animated_gif');
-  } else if (type === 'gif' && gifFrameUrl === null) {
+  } else if (type === 'gif') {
     type = t('gif');
   }
 

src/hooks/use-fetch-gif-first-frame.ts

@@ -4,6 +4,13 @@ import localForageLru from '@bitsocialhq/bitsocial-react-hooks/dist/lib/localfor
 const gifFrameDb = localForageLru.createInstance({ name: '5chanGifFrames', size: 500 });
 const failedUrls = new Set<string>();
 
+type GifFirstFrameStatus = 'idle' | 'loading' | 'ready' | 'failed';
+
+interface GifFirstFrameState {
+  frameUrl: string | null;
+  status: GifFirstFrameStatus;
+}
+
 const getCachedGifFrame = async (url: string): Promise<string | null> => {
   return await gifFrameDb.getItem(url);
 };
@@ -40,10 +47,20 @@ export const readImage = (file: File): Promise<ArrayBuffer> => {
 
 const parseGif = async (buf: ArrayBuffer): Promise<Blob> => {
   const image = new Image();
-  await new Promise((resolve) => {
-    image.src = URL.createObjectURL(new Blob([buf]));
-    image.onload = resolve;
+  const sourceUrl = URL.createObjectURL(new Blob([buf]));
+
+  await new Promise((resolve, reject) => {
+    image.onload = () => {
+      URL.revokeObjectURL(sourceUrl);
+      resolve(undefined);
+    };
+    image.onerror = () => {
+      URL.revokeObjectURL(sourceUrl);
+      reject(new Error('Failed to parse GIF'));
+    };
+    image.src = sourceUrl;
   });
+
   const canvas = document.createElement('canvas');
   canvas.width = image.width;
   canvas.height = image.height;
@@ -62,28 +79,30 @@ const parseGif = async (buf: ArrayBuffer): Promise<Blob> => {
 };
 
 const useFetchGifFirstFrame = (url: string | undefined) => {
-  const [frameUrl, setFrameUrl] = useState<string | null>(null);
+  const [gifFirstFrame, setGifFirstFrame] = useState<GifFirstFrameState>({ frameUrl: null, status: 'idle' });
 
   useEffect(() => {
     if (!url) {
-      setFrameUrl(null);
+      setGifFirstFrame({ frameUrl: null, status: 'idle' });
       return;
     }
 
     let isActive = true;
+    setGifFirstFrame({ frameUrl: null, status: 'loading' });
 
     const fetchFrame = async () => {
       if (failedUrls.has(url)) {
-        if (isActive) setFrameUrl(null);
+        if (isActive) setGifFirstFrame({ frameUrl: null, status: 'failed' });
         return;
       }
+
       try {
         const cachedFrame = await getCachedGifFrame(url);
         if (cachedFrame) {
           try {
             const response = await fetch(cachedFrame);
             if (response.ok) {
-              if (isActive) setFrameUrl(cachedFrame);
+              if (isActive) setGifFirstFrame({ frameUrl: cachedFrame, status: 'ready' });
               return;
             }
           } catch {}
@@ -92,13 +111,15 @@ const useFetchGifFirstFrame = (url: string | undefined) => {
         const blob = typeof url === 'string' ? await parseGif(await fetchImage(url)) : await parseGif(await readImage(url as File));
         const objectUrl = URL.createObjectURL(blob);
         if (isActive) {
-          setFrameUrl(objectUrl);
+          setGifFirstFrame({ frameUrl: objectUrl, status: 'ready' });
           await setCachedGifFrame(url, objectUrl);
+        } else {
+          URL.revokeObjectURL(objectUrl);
         }
       } catch (error) {
         failedUrls.add(url);
         console.error('Failed to load GIF frame:', error);
-        if (isActive) setFrameUrl(null);
+        if (isActive) setGifFirstFrame({ frameUrl: null, status: 'failed' });
       }
     };
 
@@ -109,7 +130,7 @@ const useFetchGifFirstFrame = (url: string | undefined) => {
     };
   }, [url]);
 
-  return frameUrl;
+  return gifFirstFrame;
 };
 
 export default useFetchGifFirstFrame;

src/lib/utils/media-utils.ts

@@ -19,6 +19,8 @@ export const getDisplayMediaInfoType = (type: string, t: any) => {
   switch (type) {
     case 'image':
       return t('image');
+    case 'gif':
+      return t('gif');
     case 'animated gif':
       return t('animated_gif');
     case 'static gif':