Calling for some advice,

I downloaded an animated .gif and imported it.
The file loaded in the library as about 100 bitmaps.

It's a dragon that walks and such so I want it to move across the screen.

The dragon is in my timeline as a keyframe every frame. I highlight all the
frames and convert to a symbol thinking I could tween the dragon as a symbol.

It ends up only tweening the frame that the red marker is on.
Here is the URL for the .gif if anyone wants to mess with it.
http://www.bg2.de/drachen/dragon.gif
Or I guess mess with other .gifs of your own.

I've thought to move every bitmap a little like a stop motion video, but I
know there has to be a more fundamental way.

I'm new to Flash, so I'll appreciate any help given. Thanks.