goto “PROFILE” on the top (right) of the page. Goto the bottom section “AVATAR CONTROL PANEL”. Either choose one that Mathews has or upload one from you computer. Check the size to make sure it fits. OR, if you see one that some else has, just right click on it, click “save image as” and upload through the above instructions (from your computer)
That’s how I got the avatar I have. Someone had it and I saved it and uploaded it through the profile menu. That way it is already sized and you know it will work.