1rst: see here:
http://www.opserver.de/ubb7/ubbthreads.php?ubb=showflat&Number=358127#Post358127

2nd: The other avatar is a 4 MB jpeg and a badly optimized browser could indeed try to render is continuously while scrolling causing high cpu-load.

3rd: I think this is a troll, possibly from a well known user here who wants to get some action back into the forum..

Conspiracy theory #1: Its jcl who wants to see our reaction, if its not in some way appropriate he'll close down the forum and abandon 3DGS

#2: Its our podcasting friends who need something to talk about