var begin = '<td width="193" height="379" valign="top" style="background: url(/_includes/images/side_backgrounds/';
var end = ') no-repeat top left;">';

var theImages = new Array();

theImages[0] = 'americana.jpg';
theImages[1] = 'coasters.jpg';
theImages[2] = 'dominator.jpg';
theImages[3] = 'log_ride.jpg';
theImages[4] = 'magnum.jpg';
theImages[5] = 'maxair.jpg';
theImages[6] = 'millennium_force.jpg';
theImages[7] = 'spinning_dragons.jpg';
theImages[8] = 'wicked_twister.jpg';
theImages[9] = 'wild_thing.jpg';
theImages[10] = 'xcelerator.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(begin + theImages[whichImage] + end);
}