Bah, they're big enough already!
just my opinion, but the avatar size limit prevents me from making avatars out of a lot of images...
why?
because most portrait images and good drawings that i've come across are long and narrow, not wide and short.
most of the latter type are simply background/wallpaper-types
resizing into a small resolution works up to a point, but loses a lot of detail
cropping also works only up to a point, because you can only crop so much until you start losing the important sections of the image
rotation doesn't work in most cases, too
not that i'm complaining, it only makes me work harder to narrow down the avatars to the really good ones. and i like my current one
