var theImages = new Array()

theImages[0] = '/theme/parents/img/header_blue.png'
theImages[1] = '/theme/parents/img/header_green.png'
theImages[2] = '/theme/parents/img/header_red.png'
theImages[3] = '/theme/parents/img/header_yellow.png'

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]+'" width="508" height="121">');
}