http://www.online-image-editor.com/ can crop, resize and drop every other frame from animated gifs. It shows the dimensions and filesize of the gif after every edit. Super handy, no software installation needed.
Of the 67,146 registered members checked, 13,867 (20.652%) had an avatar defined.
Of those with avatars...
1593 (11.4877%) had some sort of error described below.
821 (5.92%) were disproportionately sized.
487 (3.51%) had what appeared to be 404 File Not Found errors.
300 (2.1634%) were over the 150k file size limit.
15 (0.1%) were both disproportionate and over the file size limit.