static background image for swf

When I create an animation on a static background image,
the animation will be big.

for now i delete my background image, create a layer in html-file under my animation and set the swf animation to be transparent. I have to do this animation for animation by hand.

Would be great, if there would be a better static background handling and the possibility to create transparent swf animation. that would reduce the loading time in the web 10 times.