Go>>>>
To your profile page,
Click on customize profile, a page will display showing diff modules/sub modules,
Look closely you will see module background, click on the small box square in shape and also coloured,then a mini page will display asking you to either use colour or images as your background click on use images then it I'll ask you if you want to use a photo from your album or from the net. if it from your album you wanna select click on it wait for a while later it will display all the photos you saved to your album. select the one you need to use as your background then submit it it ll imidiately display as your background.note that you can allows change it with same procedures above..but if you want to add a photo from net as your background just copy the URL then past it no need to click on choose images just past the URL and submit.after submitting the last thing you most do is save click on save or else it won't save or won't display your new background when next you log in to your profile.....I.e without saving it your profile will authormatically go back to your previous background colour.