When I import a picture that I want applied to an object, a cube let's say... I always have the picture applied to "top of object" and then maneuver the objects top into the workspace as I want it to be viewed... That way seemed easier to me with little manipulation, than applying the picture to a side or any of the other possible ways of applying the picture.  Once in your scene... you  might want to turn off "receiving shadows" so objects in the scene don't affect the "background" on  the cube..

Steve