 
<script type="text/javascript" src="js/prototype.js"></script>
<script type="text/javascript" src="js/scriptaculous.js?load=effects,builder"></script>
<script type="text/javascript" src="js/lightbox.js"></script>
<link rel="stylesheet" href="css/lightbox.css" type="text/css" media="screen" />
prevlabel.gif and nextlabel.gif files are in the right location. Also, make sure the loading.gif and closelabel.gif files as referenced near the top of the lightbox.js file are in the right location.rel="lightbox" attribute to any link tag to activate the lightbox. For example:
<a href="images/image-1.jpg" rel="lightbox" title="my caption">image #1</a>
title attribute if you want to show a caption.		<a href="images/image-1.jpg" rel="lightbox[roadtrip]">image #1</a>
<a href="images/image-2.jpg" rel="lightbox[roadtrip]">image #2</a>
<a href="images/image-3.jpg" rel="lightbox[roadtrip]">image #3</a>