I can't really argue with the very experienced drafstmen among us about tracing and composting photos. I'll just save my opinion-making on that for when I'm older.
But as for the game thing, it's just lazy. Not using free textures, that's not what I mean. Bioware's artists gave a disembodied AI a sexy fembot body for no reason, wrote dialogue so that you could teach it sex and even gave it a camel toe, but they couldn't be bothered to create an original drawing for the revelation of an important character's face.
"Astronomy offers an aesthetic indulgence not duplicated in any other field. This is not an academic or hypothetical attraction and should require no apologies, for the beauty to be found in the skies has been universally appreciated for unrecorded centuries."