That picture is called avatar, and you can freely chose it from a pool PEEL offers you. Go to your Profile
enter your username and password and then you get a page where you can select one of these Pool avatars
in a drop down menu.
There is also the possibility to get a custom one, for that you need a picture that fits these
rules. If you can't edit it to fit these rules ask for it to be done in here: The avatar shop
. If you got that picture (.gif, 64x64, transparent, smaller than 3.4kb and facing right) go to the upload thread in the Off-topic board (Avatarize Me! The Avy Thread
) and ask for it to be uploaded as custom. You don't need that if you just chose one of the pool ones in your profile.