var theImages = new Array() 
// modify list for path to images
theImages[0] = 'images/homer1.jpg'
theImages[1] = 'images/homer2.jpg'
theImages[2] = 'images/homer3.jpg'
theImages[3] = 'images/homer4.jpg'
theImages[4] = 'images/homer5.jpg'
var j = 0
var p = theImages.length;

var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = theImages[i]
}

var whichImage = Math.round(Math.random()*(p-1));
function showImage(){
document.write('<img src="'+theImages[whichImage]+'" border="0" alt="Delta Microwave">');
}