On a photo app, put the camera shutter as a large circular button centered at the bottom of the screen. It’s right where the thumb rests and the target is big, so users can tap it quickly without aiming. Compare that to a small shutter icon in the top corner harder to reach and slower to hit, so more missed taps.

Based on what I read about Fitts's law, It can be easy for some people to believe what was shown in the amazon email without looking in that the contents don't add up.