Add gifs to tumblr from Dropbox
Drop gifs into your public folder either from the desktop or from your iPhone and they post to Tumblr. Gifs you add from your iPhones camera roll won't animate in the photos app, but they will once you upload them using the Dropbox app. Doesn't work with copy/paste of gifs though. For that you'll need to use the Email to Tumblr recipe.