When you are logged in, click on "My Profile" in the header. Once there, click on the "photos" tab. You should be able to enter all the photos you'd like there. Also, once you've entered some, you can use the photo management page to decide which will be your avatar.

One thing of note: It would be wise to resize all of your photos to 640x480, as this is the maximum size that the site will store the photos. Uploading anything larger will just waste time, and the site will automatically resize them to the smaller size.

Thanks:)... I missed the 'add photos' button!