Greasy Fork is available in English.
Undo Twitter's insistence to down-res images when viewing on its dedicated page and add a button to download the full image without the weird file extensions which don't count as actual images.
Retrieve images from Twitter in their original resolution after viewing the direct URL (usually via right-click -> Open image in new tab).
Also provide a button to download the image, automatically renaming it to the proper file extension (instead of the .jpg-large caused by Twitter's abuse of URLs).