I can tell that this is a pretty darn old thread; ... Did you ever solve the problem? (I would have no idea on my own.)
If you need a program to get avatars to be accepted, I'd recommend
www.irfanview.com' target='_blank'>www.irfanview.com. It can do so much in terms of image optimization. It doesn't
edit, but it can blur, sharpen, resize, convert images, crop, etc. (Cropping is done by clickdragging a selection, doing Ctrl+C, then Ctrl+V, then saving
that.)