I've tried to track and reproduce the avatar bug. I can change my avatar for another .PNG, but if I change it for a .GIF for example, it changes in my profile but not in my posts (alreadly refreshed). For example the posts show
http://www.abandonia.com/files/members/1/6590-thumb.png while the profile shows
http://www.abandonia.com/files/members/1/6590.gif right now. As I said if I upload a .PNG instead of a .GIF, the posts' avatar is updated all right, the posts show a 6590-thumb.png and the profile a 6590.png, but both correspond to the same latest image. There's a problem with the file extensions.