rchrdschn:
In the upper left-hand corner of the page, there is a link called "user cp" (cp = control panel). After clicking on that, click on "edit avatar" and you will be given a set of pictures to put under your name. If you wish to upload your own picture, click on the "browse" button in the lower part of the page and point to the file from your own computer that you wish to appear under your name.
The files you upload from your own computer are limited to a certain size. I'm not sure what those dimensions are but try uploading a picture. If it is too big you will be given the largest size that is acceptable to upload.