var dimages=new Array();
var numImages=10;

for (i=0; i<numImages; i++)
{
 dimages[i]=new Image();
 dimages[i].src="slideshow/image"+(i+1)+".jpg";
}
var curImage=-1;

function swapPicture()
{
 if (document.images)
 {
  var nextImage=curImage+1;
  if (nextImage>=numImages)
   nextImage=0;
  if (dimages[nextImage] && dimages[nextImage].complete)
  {
   var target=0;
   if (document.images.slideshow)
    target=document.images.slideshow;
   if (document.all && document.getElementById("main-image"))
    target=document.getElementById("main-image");
 
   // make sure target is valid. It might not be valid
   //  if the page has not finished loading
   if (target)
   {
    target.src=dimages[nextImage].src;
    curImage=nextImage;
   }

   setTimeout("swapPicture()", 6000);

  }
  else
  {
   setTimeout("swapPicture()", 500);
  }
 }
}

setTimeout("swapPicture()", 6000);