[ui] fix endless image loading

webui/src/components/display/BlobPreview.svelte

@@ -45,11 +45,15 @@
           src="/api/thumb/{address}"
           alt={address}
           on:load={() => (imageLoaded = address)}
+          on:error={() => (handled = false)}
         />
       </a>
     {/if}
     {#if mimeType == "application/pdf"}
-      <iframe src="/api/raw/{address}?inline" title="PDF document of {address}"/>
+      <iframe
+        src="/api/raw/{address}?inline"
+        title="PDF document of {address}"
+      />
     {/if}
     {#if mimeType?.startsWith("model")}
       <ModelViewer src="/api/raw/{address}" />