[twitter] provide fallback URLs for card images

f2e8aedd74 (commitcomment-64057751)

gallery_dl/extractor/twitter.py

@@ -168,6 +168,11 @@ class TwitterExtractor(Extractor):
                     if key in bvals:
                         value = bvals[key].get("image_value")
                         if value and "url" in value:
+                            base, sep, size = value["url"].rpartition("&name=")
+                            if sep:
+                                base += sep
+                                value["url"] = base + self._size_image
+                                value["_fallback"] = self._image_fallback(base)
                             files.append(value)
                             return
         elif name == "unified_card":