Picture frames form three sides of the box with a hinged door with a simple lock as the back to access the interior of the box. A smaller picture frame and a slot to put the gift envelopes compose the top. I made this for my wife at our wedding but it could easily be used for graduations or any other special occasions where you would want to showcase pictures. Fairly simple to make (it was my first real project) but definitely a ton of improvements on the design you can make.
What you will need
Choice of wood. I used poplar because of price and I wanted to paint white
Hinges and hardware
Locking mechanism and hardware, I just used a cheap mailbox lock
Glass for picture frames
Any fasteners needed for how you choose to secure pictures in frame
How to do this project
Decide dimensions you want to use for the project and cut the rear door and base accordingly. Alternatively, you could choose to make all four sides serve as picture frames and choose to secure the top to the body of the box instead, maker's preference.
Cut your picture frames ensuring that the size of the three sides match each other and are in proper proportions for the pictures you plan to display.
For the top I simply cut an additional frame the same size as the sides but glued in an additional piece of wood to form the bottom edge of a smaller picture and leave a space between it and the frame that creates the top face of the box. This space forms the slot to drop envelopes. I went with a 5"x8" photo frame on the top and about a 2"slot. I felt the slot was a bit wide but the separating piece of wood was big enough that I feel it may have distracted from the picture if it was any larger so definitely plan out your dimensions and design better than I did.
Glue up the frames. Once the frames are dry go ahead and dry fit the sides to the base and confirm the attachment locations for your hinges on the rear door. Prepare the base and top to receive the door and lock (and the door to receive lock and hinges) by cutting your recesses. This is a good time to use your router on all edges you want to round over (or any other edge style you prefer). Glue the sides to form the majority of your box.
While you wait for the glue to dry take care of your sanding on the door and install the hardware onto the door for the hinges and lock. Once the glue is dry take care of your sanding and install the glass, pictures and the spacers and fasteners you'll use to secure them. Do this for the top as well remembering that it is even more significant to be secure and have the good spacing to keep the picture and glass against the frame while it works against gravity.
Glue the top onto the sides and install the door and hardware once dry.
Cover all surfaces you don't want to paint (or finish) and carefully add your finishing touches. You could have waited until now to install glass and pictures but I thought it was easier using this sequence.