Features

Copy tweet link as VXtwitter or FXtwitter Button
Image Save Button (with custom filenames!)
Video Download Button (Downloads videos locally)
History of saved videos/images, allowing you to prevent duplicate downloads!
Hide various unnecessary buttons or tabs (such as premium, verified orgs, etc.)
Rearrange the buttons on tweets (like, reply, retweet, etc.)
Display bookmark button on enlarged image/video view

All of the above are toggleable with the extensions settings Saved Image/Video reversing to source tweet Save image in full quality right click context menu Source Code: https://github.com/usyless/twitter-improvements