First things first: print out two copies of Starry Night
Take your second copy of Starry Night and glue it to a piece of cardboard. It's ok if they aren't exactly the same size, as long as the paper fits on the cardboard.
Apply glue to both sides.
Make sure you glue all the way to the edges of the paper!
After glue has been applied, lay your painting on the cardboard. Use a piece of scrap cardboard to press and smooth out the painting.
Cut away any excess cardboard.
Once the cardboard has been trimmed, do a second pass with a small piece of cardboard, smoothing and pressing the two pieces together.
Glue both sides
If you'd like your painting to stand on its own, now is a good time to add some legs.
To make the legs: cut out two rectangles of cardboard and trim one corner off each end.
Hold each leg in place against the back of the painting and add a line of hot glue along its edge. Wait for about 20-30 seconds after adding the glue to let it cool down.