Problem with animated icon size

I've spent an hour trying to make an animated icon which size is accurate for LJ, but no matter what I do it ends up too big.

It must be a pretty dumb thing that I have to do, but I can't realize which is. When I save the icon, it says that the size is 39.1 Kb at the original window, and 107 Kb or so at the optimazed one. So the question is, how I disable the optimazed one so when I save the icon it has the smaller size? *yeah, I know it's dumb, but honestly I can't figure this out*
Thanks in advance! :)