Click Member Photos
Then click Upload Photos
on the next page you are taken to.
From there, click the "browse" button in the File to Upload section of the page. This will open a directory tree for your PC. Just find the location of the photo you wish to upload, highlight it, click "open".
After you click open, you're taken back a screen and you should have the location of your picture in the "File to Upload" box. Now you just click submit at the bottom of that page and ta da! You've uploaded a photo.