Pop Under Script that Allows Rotating Ads

Hey i need a pop under script that allows me to use a banner from a CPA company and can rotate two ads. Everything i have seen only allows you to have a new webpage popup. I need to use an image and link.

Also i want it to rotate. So like visitor one sees ad one, visitor 2 sees ad 2, and then visitor 3 sees ad 1 again.

Thanks a ton if you can do this!