title: Image change on scroll
body: <p>Following on from another <a href="https://stackoverflow.com/questions/15861645/change-image-on-scroll">SO Question</a></p>
  
  <p>This script changes an image on page scroll. However this script would be excessively large if it was for example, used for frames of a video with 200+ images. Is it possible to shorten this script for use with large number of files?</p>
  
  <p>Many thanks </p>