Нали така си викаш тази галерия
<div class="carousel">
<ul>
<li><img src="image/1.jpg" alt="1"></li>
<li><img src="image/2.jpg" alt="2"></li>
<li><img src="image/3.jpg" alt="3"></li>
</ul>
</div>
правиш така
<div class="carousel">
<ul>
<li><a href="image/1.jpg" rel="lightbox"<img src="image/1.jpg" alt="1"></a></li>
<li><a href="image/2.jpg" rel="lightbox"<img src="image/2.jpg" alt="2"></a></li>
<li><a href="image/3.jpg" rel="lightbox"<img src="image/3.jpg" alt="3"></a></li>
</ul>
</div>
после межу <head></head>
слагаш
<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" />
теглиш това
http://www.huddletogether.com/projects/lightbox2/releases/lightbox2.04.zip
и го слагаш в главната папка и си готов ;п