Your profile picture and name is visible in the top right of the screen and your profile picture will appear next to any posts you make in Discussions. Other users will be able to click on your picture to find out more about you. You can update your profile information by clicking on your name link and clicking on the About tab in your profile. Click on Change photo to upload an avatar picture and type a bio in the About section then click on Save Changes.
Alternatively, you can also update your photo and bio by clicking on your picture wherever you see it on the site.