I heard some people say that if there is one photo of you online then it doesn't matter if you post more "since your face is already in their system" they say this to feel better about posting lots of photos and video.
However this isn't true. Less information is better. If there are only a few photos of you then you can know which one someone was using, and photos grow out of date with time.
Less is better unless you have a good reason to put your face out there. It's not futile.
@futurebird It's just like how cell phone towers can pinpoint your location if you connect to enough of them.
Increasing the volume of data and the angles from which it can be seen exponentially increases the amount of information you can learn.