Is anyone else having trouble keeping your posters nice and flat inside the frame? I have the black metal frames from ShowOffDisplays and I purchased the posters from AllPosters. I went out and purchased foam board, cut it to the size of the frame, and I even purchased spray adhesive to stick the poster on the board. However, the posters still fall and get wrinkled inside the frame. They seemed to do great for about a month, but now they have all become wrinkled as they have pulled away from the foam board inside the frames. Is there a trick to keep these posters nice and flat inside the frames? I would certainly appreciate any suggestion you all might have as this is getting frustrating. Thanks!