The next time you go to post a photo on Tumblr, you may find a bunch of GIFs ready and waiting to be posted instead. Tumblr is updating its iOS app today with a new feature that lets it turn photo bursts and videos into GIFs. It works really well, automatically detecting GIFable moments in your camera roll and presenting them right alongside your other images, nearly ready to post. If you have a long video or burst, Tumblr will ask you to trim the GIF down to about three seconds. You can also choose to speed up or slow down a GIF and whether you want it to restart over and over again or if it should play back and forth endlessly, hiding the cut.