It is not safe to send photos to strangers. Online dating is mostly through text communication, and I don't know each other's personality and real situation. If the other party has bad ideas, they may find themselves through photos after giving them, then secretly follow themselves, or directly use their photos to do bad things online, and finally let themselves take the blame. It's very unsafe.
A man asks you to send him a photo, maybe he cares about your face value first. After all, now is the time to look at faces. If the looks are poor, in fact, most men will still shrink back, so online dating should first look at the looks. Secondly, I'm curious. I always want to see each other's looks after a long communication, so I want you to send photos.
Photos are relatively private things. Although it doesn't seem to cause too much loss to themselves, some people will do other things with photos, which will affect their safety and reputation.