function shuffle(o) { 
   for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
   return o;
};
   
var images = shuffle([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]);

var holders = new Array(document.getElementById("photo1"),
      document.getElementById("photo2"), 
      document.getElementById("photo3") );

var imgNdx = 0;
var hldNdx = 0;      

function RotateImage() {
   // holders[hldNdx].src = "pix/pic"+images[imgNdx]+".png";
   crossfade(holders[hldNdx], "pix/pic"+images[imgNdx]+".png", 2);
   
   if (++imgNdx == images.length)
      imgNdx = 0;
   if (++hldNdx == holders.length)
      hldNdx = 0;
}   

/* Initialize images to LAST 3 entries of shuffled arry */
for (var h=0; h<holders.length; h++) {
   holders[h].src = "pix/pic"+images[images.length-h-1]+".png";
}   

window.setInterval("RotateImage()", 7000);