http://gfycat.com/BlackandwhiteAshamedCat HTML5 video: auto-selects best format for browser, reverts to GIF where required.
http://giant.gfycat.com/BlackandwhiteAshamedCat.gif Slower. For "gif only" areas (eg /r/gifs, /r/reactiongifs)
<iframe src="http://gfycat.com/ifr/BlackandwhiteAshamedCat" frameborder="0" scrolling="no" width="320" height="260" style="-webkit-backface-visibility: hidden;-webkit-transform: scale(1);" ></iframe>
<img class="gfyitem" data-id="BlackandwhiteAshamedCat" />