I think you are looking for the preservation of old avatars. This would require using server storage space to store the old avatars. I don't see that it's worth it.
On a vaguely related note: Signatures.
Currently the old signatures persist - They are part of the page HTML files. I like the preservation of the old signatures.
I also like the current system, where one has to specifically turn on your signature. I prefer not to have it show automaticly. And I find those members who have long signatures to be annoying when they always post the signature.
I only post my admin mode signature when I think the info (links) are relivent to my message. I only post my non-admin mode signature occassionally, as it is rather lengthy.
Cheers,
Moose
Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment.
"Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham