One Use Avatars.

[dogbomb]

Hi,

I am using the avatar categories hack, along with a HUGE STACK of avatars.

Is the following possible:

When a user is using an avatar, it is no longer listed in the avatar listings so that another user cannot use it.
When they decide to change their avatar, their previous goes into the avatar list.

And possibly:

When a user is using a custom avatar (by uploading) and they decide to change it, it adds the avatar into the list (perhaps into a new category).

Thanks in advance hacking gods.