Select your callsign in the upper righthand corner of the page and select "My Account".
Scroll towards the bottom of the page and take note of the "choose file" button. You may upload a profile image there.
Also, take note of the "About Me" section. You can write an article about yourself.
You will be able to view other people's about me sections by clicking on their callsign in the "Member List" or by visiting i.e. "http://w4olb.org/me/callsign" Just replace "callsign" with the person you are looking up.