Known bug in Hack Version 1.25.1: 
In User CP when anyone changes the avatar, when the pick a category it shows the same avatars from the first category. Thx @Genie for the informations!
I will publish this weekend an update!
As provisional solution the problem can be removed as follows :nervous::
Go to the admin area (vB Control panel). Section "Avatars" -> "Options". Mark "No" behind "Avatar Category Permissions".
The update 1.25.2 will contain also new functions:
- Sorting order of the categories alterable.
- More options in the Avatar-Admin area.
- Extensive statistics to the Avatars/Categories.
- Bug Fixing in avatar_categ.php.
- and more... :bunny:
Madman