This is a nice simple project that will wow your friends and family. It will give you picture some depth and a little bit of realism to the scene.
I use 10mm MDF as the backer board. However in my case I used what I had about my shop and had to do a glue up of the MDF. You can skip this step all together if you have a piece of MDF the correct size that will meet your requirements.
I then proceeded to mill down or cut down the pieces for the decorative frame, I ripped strips down to my desired width, and then mitred them on the chop saw. I then glued the frame and used a band clamp to clamp the frame. Once it has dried I proceed to sand and tidy it.
I then need to add a smaller outer back frame around the back board so the picture is not sitting back on the wall. This is to allow the room and space behind the picture for the part of the lights the stick out so we don't break any wires etc.
I use double sided tape to mount my picture to the backer board ensuring I get it as centered as best I can. I place the decorative frame over top and and quick clamp them together so I can turn the whole picture upside down. I then drill pilot holes and screw the decorative frame to the backer board.
Flipping the picture back I proceed to drill where I want to put the lights, choosing areas where there is a light glow in the image, and the LED Xmas light will enhance it. I had originally want to epoxy the front but that turn out to be waaaaaaaay to expensive for this kid so I left it bear. You could plan ahead and put a sheet of 3mm clear acrylic to protect the picture if so desired.
And another flip so we can insert the lights. I use a small cheap set of battery powered LED xmas lights that has maybe 20 lights on it. After cleaning the holes from any blow out I poke the LED's in to the holes and simply use a masking tape to hold in and to hold the remain lights out of the way. The battery container is also the switch. So I notch out a small section of the backing frame, and hot glue the switch in.
Because I originally planned on using epoxy resin over the top of the image (but as stated was way to expensive for this kid) you may want to glue the picture to the back board and put a clear piece of acrylic of the top to protect the picture. I would router a rebate in the decorative frame to hold this... Where we have our it is out of the way and out of sunlight so it should be fine.
And there we have it a light picture that will impress your friends and family.