Can one have an expectation of privacy when in a public place such as the subway?
But if someone takes your image, and saves it, and disseminates it, against your permission, that may fall under copyright law...just copyright your image and sue everyone disseminating your image.
A woman at work told me about 10 years ago that my idea was outdated. I continued to believe what was true at one time, namely, if you take a photo or video and there are background people in the frame, you have to get signed permissions (or blur them) before publishing the photo or video. She said no one has that right to privacy any longer.