This is what I have from another posting:

<script language="JavaScript">
<!--
// Create arrays to contain all the values 
// for links and image locations
link = new Array
image = new Array

link[1]="http://www.sugarshack.com"
image[1]="/images/stores/sugar-index.png"

link[2]="http://www.clientswebsitecompany.com"
image[2]="http://www.bastropdba.com/images/services/clients-index.gif"



// Create a random number between 1 and last number
random_num = (Math.round((Math.random()*2)+1))
// Write a link and images with random array
document.write('<a href="' + link[random_num] + '" target="_blank">'); 
document.write('<img src="' + image[random_num] + '" border="0"></a>'); 
-->
</script>

Yet is is not working. I have it live at http://www.bastropdba.com/index1.html

Troubleshooting done:
the images are in the proper folders and paths are correct
I have two images