testing testing, they better both be working!
Changing avatars & signatures will update all previous posts, so you don’t even need to bother testing it like this - just look at one of your previous posts [Y]. Makes it a lot easier if you are having a bit of bother getting what you want, since all you need to do is keep a page with a post open, and then press Refresh (Usually F5 and/or some green arrows in a circle).