This game totally needs to be on other platforms because it's a comfort game that you could ideally even play in your sofa or bed or during a commute.
As for new mechanics, here are a few possibilities:
- Making the subject move to different parts of the scene
- A moving scenery where you have to snap a picture at the right moment (thunder, birds, windmill, etc)
- Changing outfits or using/moving props in the scene
- A hard mode where you have to guess the scene with no hint other than what happened before/after the picture. (I can easily see this becoming a mystery/puzzle/detective game instead of cozy tourist adventure - perhaps a different theme for each level/world?).
- Exposure/shutter speed/focus adjustments (though I can't think of any puzzles that utilize this).