Earlier quoted context omitted.
A picture is a very dangerous thing in the wrong hands. A normal picture of a person could still expose something important about them to the wrong party. Eg, "I visit the unsavory part of town", "I'm not really washing my hair", "I'm slacking off", etc. Those are mostly "real-world" concerns. There's the paranoia angle: some stranger wants your picture specifically. What could they have in mind? If you look at least…
> I'm not really washing my hair Can you explain this one?
In general, I mean that having your picture taken at the wrong time can reveal things people would rather not be revealed, even if to the photographer it looks completely ordinary and harmless.
Some people here will reference the 24/7 CCTV surveillance, but that's kept private and not published as some sort of art project. So though one could compile a video of my coming and going around the town by looking at surveillance tapes, in practice that doesn't really happen. Now random photographers and artists however are very likely to put their work somewhere public.