You're describing a different scenario. I'm talking about someone grabbing a locked phone left on a table, taking an unwanted picture (say of their genitals, ju

You're describing a different scenario. I'm talking about someone grabbing a locked phone left on a table, taking an unwanted picture (say of their genitals, just to make it problematic), and then you find out when you go to show someone your recents. One should not be able to modify the contents of a locked device but you can add photos on an iPhone. The recourse is to disable the Camera app via Screen Time and use a 3rd party camera app for when your phone is unlocked and you actually want to take photos. Unfortunately the flashlight functionality doesn't have such a workaround, but that one is more just a minor battery annoyance.