Pop-up image is blank

We used a Popup for a few weeks and then turned it off earlier this week. We created another pop-up as a clone and just changed the image. However, the popup now just shows the border and the close button but no image. I tried a Preview on the original popup and now get the same thing that the image is blank. We were using version 3.08 so I upgraded to 3.11 but get the same results. I can’t show you this happening since I can’t put a popup on our live site that doesn’t work. I can send you a screen shot if there is a place to email or upload.