It was her face. But it had been seamlessly grafted, without her knowledge or consent, onto someone else’s body: a young pornography actress, just beginning to disrobe for the start of a graphic sex scene. A crowd of unknown users had been passing it around online.

She felt nauseous and mortified: What if her co-workers saw it? Her family, her friends? Would it change how they thought of her? Would they believe it was a fake?

“I feel violated — this icky kind of violation,” said the woman, who is in her 40s and spoke on the condition of anonymity because she worried that the video could hurt her marriage or career. “It’s this weird feeling, like you want to tear everything off the Internet. But you know you can’t.”