The same way you made your current one xD
Go to "My Stuff" (Over to the left), click "Pictures", click "Upload New Picture" (Near the top middle). Once done this, open a new tab and return to this thread, right click the picture I posted, and click save as. Save it somewhere you will remember. Return to your previous tab and click "Choose File", find the picture you saved and choose that, Then click "Upload New Picture" (Be sure to give it a picture title). Once done, go to "Profile", and under "Avatar Photo", find the pic and click it. Then click "Upload My Account and Profile" at the bottom. I'll provide pics if you don't understand.