An animation is really just a bunch of pictures that are played one after another really fast (in fact, movies and television work the same way - what you are seeing are lots of pictures going by so fast that they look like they're moving).

How much time should you put between frames? There aren't any rules. Try different stuff, and when it looks right to you, it's done. Just remember that animations might not play as fast for people on the Web as they do on your own computer.

We set our animation to loop, which means it plays on and on forever. If you've only got two frames, you probably should have it loop to make sure your audience doesn't miss it the first time through.