Source: http://www.engadget.com/2014/12/11/youtube-is-testing-a-gif-sharing-option/
Click on the "share" button under any YouTube video, and you'll get three simple options: Share (for a URL), Embed (for HTML code) and Email (take a guess), but Google's video streaming site is about to get one more -- animated GIF. YouTube hasn't officially announced the new feature, but it seems to be testing it on select channels. Click on any video from Good Mythical Morning or The Idea Channel (the only two channels we found with the feature activated), for instance, and you'll be given the opportunity to make a captioned, six-second GIF like the one above. It's pretty easy; YouTube starts the GIF at the point of the video that was playing when you click "share" and allows it to be adjusted via timestamp or visual slider. Want to check it out? Click on either of the two above channels and have at it. Oh, and let us know in the comments if you find any other GIF-ready channels.
Via: Gizmodo, Twitter (WaxPancake)