Fix missing image download button (element-hq#30320)

Fixes element-hq#30319

Author: dbkr

src/components/views/elements/ImageView.tsx

@@ -620,6 +620,8 @@ function DownloadButton({
                     // Err on the side of safety.
                     setCanDownload(false);
                 });
+        } else {
+            setCanDownload(true);
         }
     }, [mxEvent]);