As of right now, the forum is set to limit avatars to 150 pixels square. If the width goes any farther, it'll create an unsightly scroll bar... the vertical dimension can be increased if there's enough demand for it.
There's no limit on the size of a signature image, but try to stay within reason (I don't wanna have to install a plugin just to limit the size of signature graphics or anything stupid like that
). It probably doesn't need to be said, but I saw it become an issue on SHC, so... there it is.
