Good news/Bad news:
Good news: Jittergram is a handy, easy-to-use iOS app for making animated gifs. You can save them to your gallery and then email them in to Tumblr, where they will animate on the dashboard. Fun. I’ll use it all the time and happily tag the posts.
Bad news: When I upload the same saved file from my gallery to Twitter, it’s stone still. Additionally, the app’s share options merely post text links to branded pages housing your animations. If I wanted to ask people to click too many times to see something cute I did, I’d go write for nytimes.com.
Still, check it out.