For those of you who are looking to add an Avatar to your Screen Name (The little picture on the left below your name), first you must choose a picture that you would like and resize it so that it is no larger than 85 pixels (Either wide or high).

After it has been resized, it must be saved in Jpg or Gif format and the file size needs to be less that 7k.

Once the picture is ready, click on "Settings" at the top of the page (Pic 1)

Then scroll down to "Avatar" and click "Upload my Picture" (Pic 2)

When the dialog box appears, Click "Browse" and select the picture you have prepared. (Pic 3)