Ok, your image didn't need to have the IMG tags around the URL, so I fixed that. Other than that, it was working. I think it might have been because you have 20 threads loading, and the slides are randomized each time the slider is loaded. The first time, the custom content item was the very last item, next it was 17/21, next it was 6/21. So you may just need to lower your thread quantity, or wait longer to get through the threads to see the custom content item.