You may heard about Twilk, which will allow you to make an image with the users you follow or following you (or both).
I just wrote a web application with the help of csharptwitt, this will create an image with the profile pictures of your friends.
The missing functionalities with Twilk are mainly two things
1. It will not have a facility to check Following and Follows back
2. It will not update your twitter background (You will have to manually do that), I tried to do this, but not succeded yet, if any one can help on this that will be a great help.
right click and save the image displaying, and use that image as your twitter background.
Source code here: