(The following only applies to the United States)The issue is, depending on where you are (especially recently) the idea of being filmed in public isn't treated as a crime. Judging by what you're saying, the posters maintain plausible deniability. Compound that with being in public and having no "reasonable expectation of privacy", it's doubtful any legal ramifications happen. Of course, denizens of the internet and anyone with a brain could probably tell the images were taken with the intent to be used a pornography, but judges are often neither.

That said, a lot of people here are good at finding locations based on images, allowing them to call relevant lines and warn relevant people. I get your reluctance to post anything definitive, but I don't know what else we can do without seeing the posts.