John, the way I make my puzzles is to spray the picture (photo) with a clear lacquer. I also often spray the board I am going to fix the photo to with a clear or a coat of contact (Let it dry properly.) For the photo, this protects the surface and doesn't allow the contact to bleed through if put on a bit thick. For the board, this keeps the contact on the surface, not allowing it to seep into the board as this will make it loose grip.
I then spray the board and the back of the picture with with contact (Pressure pack) both vertical and horizontal. When both are tacky I press them together and using a laminate roller roll the picture down hard. I will then apply a 2nd coat of lacquer. after lightly cutting back the 1st coat with 360g paper. After I have cut the puzzle I make it up, and once again cut it back with 360g before applying a final coat of lacquer. The final coat not only protects the puzzle and provides a nice finish, it also serves to blend in the cut edges so they do not show white.