Tap Settings on the top right, then go to the My Settings box on the left side of the page, hit Edit Avatar, then a Custom Avatar box will appear in the middle of your screen. Make sure that the Use Custom Avatar circle is checked/black. You'll probably want to select Option 2, Upload Image From Your Computer. Tap Browse, find a small pic you like on your personal device, and upload it. Should appear automatically once done.

If you're trying to use a stock photo from H2, there may be a tech glitch. I cannot view any of them, myself.