yea, it happened to me today as well. my best guess is it's a bug in the forum software. in the meanwhile, i guess for anyone who notices that their avatar is inappropriately sized, if you wanna go about fixing the problem yourself, you can simply resize the image you use for you avatar to something smaller, then re-upload it at the more appropriate size. this can all be done quickly and easily in MSPaint, or any other photo editing software.