Auto skrinking of avatars?

[Neo]

I'm sure this forum could be modifyied on that way so that user can pick if he wants to use an avatar under 80*80 or a bigger one shrinked to size preset by the admin.

There are some problems with that. See further points.
1. Big avatars require a lot of space
2. Have you thought about telephone modem (28/56k) users?
3. If the routine that shrank the avatars would be client-sided, there'd be much more code to download and to process, thereby slowing down the page downlad.
4. If the routine that shrank the avatars would be server-sided, the server would have to be a powerful computer to deal with many of that routine calls.