FancyZoom is a nice image lightbox plugin. Here is the simplest way to use it.

First you should have a way to initialize it when DOM is loaded , here we use addDOMLoadEvent introduced in Compatible Javascript code addDOMLoadEvent . Its better than old IE's load event.

 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3c.org/TR/xhtml11/DTD/xhtml11.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
 <title>title</title>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<script src='FancyZoom.js' type='text/javascript'></script>
<script src='FancyZoomHTML.js' type='text/javascript'></script>
<script src='addDOMLoadEvent.js' type='text/javascript'></script>
 
<script>
 
addDOMLoadEvent(setupZoom);
</script>
<body>
<div  style="width: 515px">
    <a href="pic.png">
      <img src="pic.png" alt="" width="515" height="190"></a>
 
</div>
</body>
</html>
 

Enjoy it!