Scroll banner with long pics?

Im making a picture scroller that has no interaction whatsoever just plays on its own. I have 4 images that are 800x100 each and have combined them into one movieclip. However i have a problem! Do to the size i dont want to have a huge timeline for this thing. Im fairly new to actionscripting and i know this would be an easy fix if i could code it. It needs to be seemeless so it continuously shows these 4 pics. Here is one of the images for reference.