I applied purple and white Liquetex acrylic paint on the box. I made sure not to mix the colors together entirely, so you can see a little of the white to show through the purple. This gives it a sort of marbelized effect.
Next I applied the paint on the outside using angled brushstrokes.
I glue the photo on and allow it to dry. The last step is to paint very carefully around the bird to cover the blue background. I apply a coat or two of varnish to seal in the paint.