It isn’t a matter of whether taking pictures of people is illegal or not, instead you should be asking like: Is it illegal to take pictures of people in public places? Well, generally, you can snap pictures of people in public areas; there is nothing wrong with that, but in private settings, you can’t just do that, and if you still go about it, there can very well be some legal action taken against you.
Public Spaces vs. Private Property

It mainly depends on the location of the shot, not a single doubt in that.
Generally, you don’t need to ask for permission if you photograph a street, sidewalk, park, or beach since these are public places. There isn’t such a strong expectation of privacy in people when they use public spaces, so the taking of photos of daily life is mostly permitted. No one can make you legally liable for that.
On the other hand, if you are on a private property like a mall, store, restaurant, office, or someone’s house, the regulations vary. Like, pretty much, the owner or manager of the property can determine if photography is permitted. They can request you to cease or vacate if you are told to do so. You should comply with their order. Not doing so may result in trespassing problems.
Note: Always check your legality when you are taking pictures. It is generally okay to take pictures in public places, so you can go about it whenever you’re in a public place. Private places are governed by their respective rules.
Reasonable Expectation of Privacy
This is among the most crucial ideas in the U.S. privacy law.
Suppose an individual reasonably expects their privacy is protected, the act of photographing or sharing their photos without their consent might be against the law. Though, surely, in general, people do not expect to be protected when they are in places open to the public, such as streets, parks, or public events, so it is lawful to take pictures in such places. That’s perfectly fine.
However, privacy is generally assumed in private areas like home, bathrooms, changing rooms, or other similar spaces. Taking pictures of people in such situations without their consent might be illegal. Although you might be physically located in a public area, if you are using zoom lenses to get images from private spaces, you might be going too far. That may not be illegal, but it can very well turn against you.
When Taking Photos Becomes Illegal
In fact, there are several instances where one should not take photos. Let’s see those one by one.
First and foremost, a photo shot in a place where privacy could be assumed such as a restroom or a bedroom may be regarded as an invasion of privacy or voyeurism.
Second, if one keeps on taking pictures of another person so as to make them feel threatened or uncomfortable, the act can be equated to harassment or stalking.
Third, capturing pictures of someone’s private body parts without permission, even if they are in a public place, is prohibited by the Video Voyeurism Prevention Act and various state laws. So you can’t just go about it and such violations may result in serious legal consequences.
Posting or Sharing Photos Online
As a general rule, no doubt, if you have legally photographed someone in a public place, you should ordinarily be able to post that photo on the internet without any problems for personal or informational kind of use only, like on social media handles or blogs.
But the thing is, with this as well, there are restrictions. Essentially, a person’s image cannot be commercialized without a formal agreement from the person (model release), which is mostly given only for advertisements or promotions.
And then, no doubt, distributing images for the purpose of defamation or maliciously misleading the community may cause you to be liable for legal actions like defamation or false light as well.