Its easy enough to do.
Scroll to the very top of this page, you will see your name, and to the right of it, the envelope icon and the bell icon.
Click your name, then click "my profile".
Once your in there, hover your mouse over the grey shadowy picture of what would be you (left hand side). Then click "Change" in the top left of the picture.
choose a picture and upload. just then crop it as you want it, and then click Save.
Welcome to you both as well!