function initialize(){  
  if((document.getElementById('thumbnails'))&&(document.getElementById('bigImage'))) {
    imgs = new Array();
    imgs = document.getElementById('thumbnails').getElementsByTagName('img');
    for(var i=0;i<imgs.length;i++) {
      a = document.createElement('a');
      a.href = "";
      a.onclick = function() {
        bigimg = document.getElementById('bigImage').getElementsByTagName('img')[0];
        newsrc = this.getElementsByTagName('img')[0].src.replace(/thumb/,'display');
        newalt = this.getElementsByTagName('img')[0].alt;
        bigimg.src = newsrc;
        bigimg.alt = newalt;
        document.getElementById('imageCaption').innerHTML = newalt;
        lis = this.parentNode.parentNode.getElementsByTagName('li');
        for(var j=0;j<lis.length;j++) {
          an = lis[j].getElementsByTagName('a')[0];
          an.className = an.className.replace(/showing/,'');
        }
        this.className += "showing";
        return false;
      }
      di = document.createElement('img');
      di.src = imgs[i].src;
      di.alt = imgs[i].alt;
      a.appendChild(di);
      imgs[i].parentNode.replaceChild(a, imgs[i]);
    }
  }
}
    
Event.observe(window, "load", initialize, false);