I can successfully change the background image using the following:

jQuery(document).ready(function($) {


 $("div#largeimage").randombg({
 directory: "http://path/to/imgs", //directory to image folder
 howmany: 3 //how many images are in this folder
 
 });
 
 });


But, what I want to do is change this ONCE per user session. So instead of change this on every refresh / page load
I want to load it once, store that setting in a cookie/session, and not do it again until the next session.

Hopefully that makes sense. Is this possible?