Even if it's legal it should really be illegal purely on the fact that it was posted maliciously.
I don't think you've thought through the ramifications of what you're wanting.
The principle you're advancing is that public images or video should be treated as though it was an invasion of privacy? How would this work for the media?
If someone was a famous nudist 20 years ago, and now condemns nudity, you're saying if someone posts an image to remind them and other people what they were like, that should give the uploader a criminal record, and I assume be put on a register?
This malicious aspect, can one person posting it be legal because its not malicious, while someone else posts it and they get a criminal record? What if you post a picture with no malicious intent but the person in the image says you were malicious. What happens then?
In this case the person is an adult who is responsible for dressing herself. Doesn't she have any responsibility?
What if this was a man not realising his zipper was undone and he wasn't wearing boxers?