diff --git a/web_app/static/script.js b/web_app/static/script.js
index 441a4ed..229021e 100644
--- a/web_app/static/script.js
+++ b/web_app/static/script.js
@@ -671,6 +671,10 @@ async function generatePoster() {
             showDownloadButton(imageUrl, data.filename);
             loadingOverlay.style.display = 'none';
         };
+        img.onerror = () => {
+            loadingOverlay.style.display = 'none';
+            showToast("Error: Failed to load the generated poster image.", "error");
+        };
 
     } catch (error) {
         console.error("Generation failed", error);