Start by removing the hardware on your wooden box including hinges, latches, etc.
Paint corners & edges
Paint all the corners and edges of the box. Don't worry about the middle, you are going to cover any unpainted areas with scrapbook paper.
Cut out pictures
While the paint dries, cut out the photocopies of your Christmas card pictures and old cards.
Trace box outline onto paper
Once the paint has dried, you'll place each side of the wooden box atop your scrapbook paper and trace the outline.
Cut outline pieces
Cut the outline pieces smaller than the traced area, you want the cutouts to leave a little margin where the painted box edges can be seen. Double check the size by laying each piece atop its designated side.
Mod Podge scrapbook paper to box
Use the sponge brush to paint on a medium thick layer of Mod Podge onto 1 surface of your box. Next, paint a medium layer of Mod Podge onto the back of the scrapbook paper piece that matches that surface. Eyeball where it should be placed, and gently lower it into position. You'll be able to lift and reposition it if necessary or tweak by a couple of centimeters.
Smooth scrapbook paper down
Smooth the freshly applied scrapbook paper from the center out. Roll the brayer on top to endure there are no bubbles, or if working on the inside of the box, use the squeegee to smooth it out. Simply wipe up any excess Mod Podge that is squeezed out the edges.
Cover all sides & let dry
Once all of your sides are covered with scrapbook paper, let the box dry for 20 minutes.
Smooth entire surface
Determine where you want each photo, and whether any will overlap. Start with the bottom layer of photos, and add a thin layer of Mod Podge to the back of each photo. Mod Podge a medium layer across the entire surface of the box side you will be working on. Add each photo and smooth outward from the center. Once all of the photos have been added to that surface, use the brayer to roll each photo flat. Do not use the squeegee on regular paper, or it may tear.
Seal with layers of Mod Podge
Let the box dry for 20 Minutes, then add a layer of Mod Podge atop the photos and the entire surface. Add 2 to 3 layers of Mod Podge to each surface of the box, but be sure to let dry each layer dry for 20 minutes or it will cause bubbling.
When your box is dried, reattach the hardware. The old hole will be buried under scrapbook paper and Mod Podge, so you will make all new holes.