Fix GUI debug code

cache.py

@@ -106,8 +106,15 @@ class ImageCache:
                     except (FileNotFoundError, Image_module.UnidentifiedImageError):
                         pass
             if image is None:
-                async with self._twitch.request("GET", url) as response:
-                    image = Image_module.open(io.BytesIO(await response.read()))
+                try:
+                    async with self._twitch.request("GET", url) as response:
+                        if response.status != 404:
+                            image = Image_module.open(io.BytesIO(await response.read()))
+                except Exception:
+                    pass
+                if image is None:
+                    # use a blank white image as a fallback
+                    image = Image_module.new("RGB", (10, 10), (255, 255, 255))
                 img_hash = self._hash(image)
                 self._images[img_hash] = image
                 image.save(CACHE_PATH / img_hash)