Popup showing up with no content

I installed the popup plugin tonight but the image wont show up. I’m confident it is because of supercache plugin because when i turned that off, the image seemed to work. However, I really want to keep the super cache plugin. How do I make them work nicely together? I’m uploading two images of my settings and also the image not working. I am going to turn off the popup so my users aren’t confused. Thanks for your help!