var theImages = new Array();

theImages[0] = 'top_right_photo.gif';
theImages[1] = 'top_right_photo_02.gif';
theImages[2] = 'top_right_photo_03.gif';
theImages[3] = 'top_right_photo_04.gif';
theImages[4] = 'top_right_photo_05.gif';
theImages[5] = 'top_right_photo_06.gif';

var j = 0;
var p = theImages.length;

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

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