Lisa,
Upload (or find) the picture that you want to use to photobucket or any pic hosting site. Under 'edit profile' click on the little box to the right of "page background". That opens a dialogue box that gives an option to select color or use image. Check "use image" and paste the link to the image you want to use. It looks like you could also use a picture from your EFC album, though it worked better for me to link to an image hosted outside of ECF.