diff --git a/frontend/src/components/DownloadCenter.tsx b/frontend/src/components/DownloadCenter.tsx
index cf4a61a9..9facb718 100644
--- a/frontend/src/components/DownloadCenter.tsx
+++ b/frontend/src/components/DownloadCenter.tsx
@@ -84,10 +84,13 @@ function StatusPill({ job }: { job: DownloadJob }) {
 }
 
 function Thumb({ job }: { job: DownloadJob }) {
-  // Prefer the source thumbnail; fall back to our generated poster for thumbnail-less sources.
-  const primary = job.asset?.thumbnail_url || job.poster_url;
-  // A remote i.ytimg.com thumbnail 404s once the source video is deleted/privated, leaving a
-  // broken image. On load failure fall back to our always-present self-hosted poster.
+  // Prefer OUR self-hosted poster: it's always present on disk, never expires, and is same-origin, so
+  // a source-CDN signature expiry (Facebook's fbcdn URLs expire within days) or an ad-blocker/Shields
+  // rule on the source domain can't break it. The source's remote thumbnail_url is only a fallback for
+  // the rare poster-less asset (a thumbnail-less source whose ffmpeg frame-cut also failed).
+  const remote = job.asset?.thumbnail_url ?? null;
+  const primary = job.poster_url || remote;
+  // On load failure (a genuinely missing poster file) fall back to the remote source thumbnail.
   const [src, setSrc] = useState(primary);
   useEffect(() => setSrc(primary), [primary]);
   return (
@@ -99,7 +102,7 @@ function Thumb({ job }: { job: DownloadJob }) {
           loading="lazy"
           className="w-full h-full object-cover"
           onError={() => {
-            if (job.poster_url && src !== job.poster_url) setSrc(job.poster_url);
+            if (remote && src !== remote) setSrc(remote);
           }}
         />
       ) : null}