A cash grab in the most literal sense. You have to spend average 30 diamonds for 1 image or 2 dialogue lines. I should add per relationship level you get 2 or 3 diamonds back. Making it not even worth the cost, spend 5 bucks to unlock at most 2 images. It shames you with your choices as well "spend diamonds or be a total prick no one likes". A greedy guilt tripping cash grab is the name of this game.