I didn't really keep track for the subsequent series, but I was (and am) amazed by the paintings and other images that the crew hung in their quarters. So often (aside from Data's work and the art studio scene with Picard) they're space-scapes or starships. I know why. To remind us that -- OoooOOooooh! We're in SPACE! But if I were on board, something I could see out the nearest porthole would be the last thing I'd spend a single replicator credit on to put up as a poster. No, I'd want scenes from my own planet. Or family. But what's your in-universe explanation?
Why do people who live on Earth put up paintings of landscapes? Or photos of people they see every day?
Besides, most of the time, all you'd see "out the nearest porthole" would be an empty starscape, or warp streaks going by. The paintings are of particular vistas that are of exceptional beauty or interest. Yes, the paintings and the view out the window are both "space" -- but then, a view of the Grand Canyon and a view of the airshaft out the window of a downtown apartment building are both "Earth," yet few would consider them equivalent.