That image looks not like the one I posted. The colours and picture are roughly like the background image in the picture 2 posts above, but the moon is almost twice as wide as the reflection in real. Your PNG looks like a paletted 2-bit version of some background, and I can't even see the moon. I'm just looking for the image to reproduce the real backdrop for a replica machine.
"... a paletted 2-bit version of some background..."
Sorry, but have you ever seen a complete Space Invaders machine?
The image you posted is the backdrop artwork from the older version of MAME, and was created YEARS ago, back when MAME's artwork capabilities were "not as advanced."
The image I posted is a copy of the ACTUAL SCAN of the backdrop from a Space Invaders cabinet. The actual backdrop is a dark blue; when the light inside the cab shines on it, it will look a different color.
The moon is a separate piece, that sits in front of the backdrop, but still behind the reflected image. See below... (which is a copy from a SCAN of the actual moon)
Play the game in MAME (a current version, not some pre-0.106 version), turn off bezels, and you'll see the image "you're looking for," which is created with two pieces of artwork.