Shelley,
Near the top of the forum, you will see a long, horizontal, light gray rectangle starting with the words "Welcome back." In that same line you will see "User CP." Click on "User CP." You will see a column menu on the left. Under "Your Profile" choose "Change Avatar." You can select the "Browse" button in the "Custom Avatar" section to choose a picture from your hard drive or you can paste a URL.
Near the top of the forum, you will see a long, horizontal, light gray rectangle starting with the words "Welcome back." In that same line you will see "User CP." Click on "User CP." You will see a column menu on the left. Under "Your Profile" choose "Change Avatar." You can select the "Browse" button in the "Custom Avatar" section to choose a picture from your hard drive or you can paste a URL.