I have imported images of planets and used them in place of or over the moon image. To do this, create your scene and make sure the moon image is not visible. Next, Create a 2d disk or a sphere and apply your pic to it. Create a spotlight and place it really close to the front of the sphere. Widen it enough so that it will light up everything. Then make sure the light and the sphere both do not cast shadows, as a moon reflects light off the sun, and has no shadow. Next, link the spotlight to the disk or sphere. By doing this, you can resize Without having to worry about fiddling with the the light size. And because you used a light to illuminate it, you can change the density and color at will, so there's no messing around with the ambient lightm, and you can easily create moon phases: full moon, helf moon, etc. Hope this helps.