Arrange your selected images over a large poster board, grouping them together neatly. You can choose to use any type of printed image. The images can be placed in small groups scattered around the poster board, placed in a spiral design, or placed in one large group. If you don't have a lot of images, you can use a smaller piece of poster board. You can also use cardboard, wood, plastic or any other hard flat surface.
Dip a sponge applicator or 1-inch wide paintbrush into some decoupaging glue. This acid-free glue is a decoupaging material that is available with either a shiny or matte finish. Wipe away excess glue on the side of the jar and apply a swipe across the back of one image.
Press the image back to its place in the collage. Attach the remaining images to the surface by applying more decoupaging glue to the backs of them one by one, and pressing them back on their original spot.
Paint a thin, even layer of the decoupaging glue over the top of all the photos, completely covering them. At first, the formula will appear solid white and cover the images, but when it dries the finish will be completely clear and the images will be visible.
Allow the decoupaging glue to dry before hanging the collage.