im feeling lazy, none of the site i found would work so if anyone would like to hook me up with a gif of my going into snake from this video at 2min in I would really appreciate it! http://www.youtube.com/watch?v=j43Mo7pSOS0
In the Animation window, make a new frame for each frame of your animation. For the one you posted, that would be 7. Layer and adjust visibility for each frame so that the correct picture is showing, adjust the time for each frame to whatever speed you want, and save as a GIF.