diff --git a/superset/dashboards/api.py b/superset/dashboards/api.py
index 79ce952f25c8..bf77d372d6d8 100644
--- a/superset/dashboards/api.py
+++ b/superset/dashboards/api.py
@@ -1342,6 +1342,8 @@ def thumbnail(self, pk: int, digest: str, **kwargs: Any) -> WerkzeugResponse:
         self.incr_stats("from_cache", self.thumbnail.__name__)
         try:
             image = cache_payload.get_image()
+            if not image or not hasattr(image, "read"):
+                return self.response_404()
         except ScreenshotImageNotAvailableException:
             return self.response_404()
         return Response(