Lightframes for backlit pictures or Lightboxes can cost a fortune and they mostly have a unattractive cable to the next socket. Here is a low-cost version that you can put on every wall or on a shelve.

What you need:

-a deep frame (I took the RIBBA frame 50x50 from IKEA the deeper version)
-battery-powered LED light chain. Smaller and more LEDs are better
-mirroring adhesive foil
-cutter scissors and glue or doublesided cellotape
-and a nice picture of course :-) (you can order backlit pictures in different sizes on some poster printing websites)

Step 1: Mirror, Mirror

Easiest way to get the mirror back is to put mirroring foil on the paper that is already in the frame.

Make a grit on the back of the paper according to the number of LEDs you got.
I had 36 LEDs, so I mad a grit with 8cm distance between the LEDs and 5cm on the sides.

Press the tip of a pen in the spots you want a LED and it will show on the front side.

Step 2: Battery Case Notch

So that the frame will be flat on the wall you need to make a notch for the battery case.
Mark the case size on the back of the mirror paper, the wooden back piece and on the removable inner frame of the frame. Cut out all these pieces, so the case fits nicely. Ideally the swich is accessible like that. Il will be quite secure once you fixed the wire

Step 3: Place the LEDs

Now place all the LEDs on their place as marked. Put small strips of the mirroring foil on both sides of the LEDs to fix them. After this step fix the mirroring paper on the wooden back piece with glue or doublesided cellotape so it will stay flat. If you have excess wire fix it on the back side, so that you can move the battery case but it wont fall out by it self.
If you want to increase the difficulty of this step add a cat that loves to play with wires :-).

Step 4: Final Step

Now you just have to assemble the pieces and your done!
I put my picture in front of the glass in the frame. The more distance to the LEDs the better and I like the matt surface.