Facebook Creative Hub - A new way to create & preview mockups for ads with Facebook
Tweeig - Repost any tweet to Instagram or other social media
Enhance - Find, crop, edit, & share pics to social. Made by Hootsuite.
TweetPik - Easily convert tweets to images SVG, PNG and JPG
Typorama - Typorama: Text on Photo Editor is a Typography Art and Poster Maker application created and published by Apperto Ltd.
Twinsta - Sharing tweets on Instagram has never been so easy!