title: Image disappears when scrolls to edge of viewport
body: <p>Some of us are wondering why the images in this tutorial demo disappear as soon as they touch the top - scroll slowly on slide 3 in the demo:</p>
  
  <p><a href="http://webdesigntutsplus.s3.amazonaws.com/tuts/338_parallax/src/index.html" rel="nofollow">http://webdesigntutsplus.s3.amazonaws.com/tuts/338_parallax/src/index.html</a></p>
  
  <p>i havent been able to figure it out. the tutorial is here: 
  <a href="http://webdesign.tutsplus.com/tutorials/complete-websites/create-a-parallax-scrolling-website-using-stellar-js/" rel="nofollow">http://webdesign.tutsplus.com/tutorials/complete-websites/create-a-parallax-scrolling-website-using-stellar-js/</a></p>