Maybe you aren't aware but this is a specific issue with the technology you are inquiring about. It is literally impossible what you are asking and the conceivable nefarious uses lead one to that conclusion so you clearly have not thought this through as that has been specifically an issue combatted on this very platform.
Also this being literally your only post on this account is what made me suspicious in the first place.
"Uh hey anyone know any apps I can use to make sure nobody else can screenshot or share the pictures or things I post?"
You don't see how that looks sus as all fuck?
This has to be a bit