first click on "Profile" at the top of the page, it looks like this:
then navigate to the menu bar on the left of your profile, it looks like this:
click the "Forum Profile Information" option highlighted above in red.
you should see an upload option for an avatar
(important note: all avatars must be 75x75 pixels in dimensions (or smaller) or else they may have trouble uploading. i believe anything above 5kb will also have problems)
