Forum Avatar Dimensions

This is just a quick query about something that has just began bugging me recently.
Can anyone explain HOW some Sythe users are able to have a drastically bigger avatar size, when the current dimension limits are 80x80 pixels?
I have seen some members that are NOT moderators with avatars at the size of 160x120 pixels.
Is this a flaw with the VB boards that some members have discovered? Or is it directly linked to the permissions of certain usergroups on Vbulletin?
Currently, all the "non-moderators" with larger avatar sizes are $25+ Donators (or more), so could this also be a contributing factor?
If this IS an unlisted Donating perk, please let me know.

Oh and if you don't want to post the explanation here, a PM would be greatly appreciated

 

Anyone can do this, it has nothing to do with permissions/ranks/groups. Vbulletin uses the getimagesiZe function to make sure the image fits in the criteria, however, users can modify the headers in gif's and edit them (hexedit) so they appear to fit in the criteria although they are larger. Hope this helps