If you have registered and have a login ID and password already, look to the top right of your screen and click on [Edit Profile]. You then get the option of selecting the avatar tab from the edit profile screen and choosing to upload an avatar image of your choice. Before selecting [upload] make sure the [enable avatar] radio button is selected.
Selecting an image for yourself is exactly the same thing as an avatar, at least in the context of this website
regards
Andicati
.