Its pretty easy.

Pick out your digital picture and adjust the size by cropping and resizing with microsoft paint till you get it to about the right size.

Upload it to the "Visitor Picture Upload center" located at the top of the page. Check your email for the URL or pick the picture in the gallery and copy the URL.

It should look something like this:

http://www.piscatorialpursuits.com/uploads/UP3559.jpg

Go to your profile and pick "select a different avatar image". At the bottom of the page paste the URL for the photo you uploaded. Your photo should now be at the top of that page, hit "select this avatar". Once back at your profile page be sure to hit the update profile button or it wont save.

hope this helps