Preloading each pic seperate

Hi, I’ve followed this tutorial:

http://www.kirupa.com/developer/mx/photogallery.htm

which works perfect, but I would like to know how to create a small percentage preloader for each seperate pic thats being loaded…

Can someone help me out on this PLEASE?
BTW the movie this image gallery is in, is a swf that’s being loaded into another movie.