not sure when it was, it might have even been back as far as th 'after dark' screen saver for win 95/98 but there was a feature there that would set the current wallpaper to the image displayed in the screen saver. Is that something we could do with the in house screensaver? We are already getting a list of images, so I would think it would be relatively easy to use said list the fire off the wallpaper change command with the current item in the list as the base for the next wallpaper change.
two reasons come to mind. first, it's cool and second it should theoretically make returning to a windows state faster as it would only have to draw the taskbar and icons over top the same image.