Polarr Photo Editor 3 - The most powerful photo editor in the web.
Twiger - Share tweets on Instagram
Fenetre App - Picture in picture for your mac.
Twinsta - Sharing tweets on Instagram has never been so easy!
Darkroom 2.0 for iOS - The photo editor for enthusiasts, rebuilt from the ground up
TweetPik - Easily convert tweets to images SVG, PNG and JPG