diff --git a/services/web-ui/public/index.html b/services/web-ui/public/index.html
index cad3c78..0356c08 100644
--- a/services/web-ui/public/index.html
+++ b/services/web-ui/public/index.html
@@ -541,7 +541,12 @@
 
   function setImgSrc(img, src) {
     img.src = src;
-    img.onload = () => img.classList.add('loaded');
+    img.onload  = () => img.classList.add('loaded');
+    img.onerror = () => {
+      delete state.thumbCache[img.dataset.assetId];
+      img.classList.remove('loaded');
+      thumbObserver.observe(img);
+    };
   }
 
   // ── Init ────────────────────────────────