var theImages = new Array() 
for (i = 1; i <= 20; i++){
theImages[i-1] = 'http://stangplanet.com/images/home_banner/mustangs/' + i + '.jpg'
}
// do not edit anything below this line
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));
document.write('<img src="'+theImages[whichImage]+'"');