Gallery is unlocked via a side quest with Ember! Then you need a Stone she sells and you can craft it in your Room at the desk.
For older scenes, yes we do Upgrades for old scenes from time to time! There is several planned since they don‘t Look as good anymore.
We recently made a poll on Patreon with a test scene with Sounds and moans in scenes that was very Well recieved! So that one is also coming but will take some time.