Second rule of photo print mounting
No 4-corner press!
Second Rule Of Photo & Print Mounding
Unless you are going to mount the entire image to its backing (for example, in a heat press or with some sort of spray mount), attach the print from the top only. Do not attach the bottom or all four corners. Art is usually on paper and paper expands and contracts. If the print is attached on all four corners and expands, it warps or buckles!