Change logon wallpaper each boot

So, I have the backroundchanger.exe from Brink's tutorial, but wondered - How can I setup an automatic wallpaper change each bootup? Say for example rotate through the images in my shared picture folder.

The program in the tut doesn't seem to allow this - is there any other way?

Thanks
D

You might appreciate the little script I use. Find it here: Logon Wallpaper - automatically change w/ every logon