Click Control Panel up there in the top right... then on the right of that screen you'll see where you can select a profile image. For some reason uploading an image never works for me so I allus point to an image already on the net using the URL option.
Is it a photo of your own or one from the web? If its your own jpeg you need to host it somewhere, like photobucket.com. If its from the web you don't need to do this, just right click on the image and copy the image URL. They paste the image url into the section in control panel where it says "upload external image" or something like that.
