Change User Avatar

Probably a very obvious question, but one I can't seem to solve through poking around, but how on earth do I change my avatar for the forums? I'm sure its in some obvious place I've not found yet.

I believe avatar’s are 150x150 pixels. You change it by going to your profile then pasting the link in the Tag URL. ^^

Thank you! :) I wasn't sure what the tag part meant, that makes sense :D

Den => Baneful's Profile => Edit Account Settings (scroll down) => Tag URL