While you’re correct, the “specific wavelength” images still seem like cheating. Sure, purple would be pretty hard otherwise (and that purple color is a typical false color for nebulas, while the sun one is not typical for most people to see), the cyan shouldn’t be hard to do. There’s plenty of satalite pictures of earth with the right color, or the atmosphere. Maybe they don’t want too many earth pictures, but they could ditch the white clouds for Pluto or something. White is easy. Green would be harder to replace.