var theImagesD = new Array()

theImagesD[0] = 'thumbs/d1.gif'
theImagesD[1] = 'thumbs/d2.gif'
theImagesD[2] = 'thumbs/d3.gif'
theImagesD[3] = 'thumbs/d4.gif'
theImagesD[4] = 'thumbs/d5.gif'
theImagesD[5] = 'thumbs/d6.gif'
theImagesD[6] = 'thumbs/d7.gif'

var j = 0
var p = theImagesD.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = theImagesD[i]
}
var whichImageD = Math.round(Math.random()*(p-1));
function showImageD(){
document.write('<img src="'+theImagesD[whichImageD]+'">');
}