image.html

<img class="lazy" src="placeholder.gif" original-src="original-image.jpg" />
<noscript>
  <img src="original-image.jpg" />
</noscript>

lazyloader.html

<script>
  $(function(){
    $('img.lazy').lazyload({threshold: 30});
  });
</script>

loader.html

<script src="jquery.js"></script>
<script src="jquery.lazyload.js"></script>