Uninvited voyeurs
Beautiful and natural bodies also have secret and annoying admirers.
Last summer in Crete, I noticed a guy (shorter than me, hipster beard and impressively trained abs) "inspecting" the sunbathers under his sunglasses. He then retired to the edge of the beach and meditated in what is called the "full lotus" position. I left my girlfriend alone for a while (doctor advised to swim a lot) and when I returned to her, she told me that this guy must have taken a picture of her with a tiny pen camera before he disappeared.
I did not find any good words to entertain her frustration: "He was naked, no backpack, where was the pen hidden?"
Have you ever experienced an uninvited camera click immortalizing your naked body?
Had someone do this last summer at a CO beach I visit. I asked her why she was taking photos of people without their permission and she just kept walking. She took a photo of the great back-ground to the beach, big sandstone cliffs, but there was a naked guy lying right in the middle of her shot , she even zoomed / adjusted quite a large tele-photo lens. This is the only time I've witnessed it but I've asked others and it happens often but usually it is guys taking photo's of girls as in your case.
Not sure you can do anything. CO beaches are public not private beaches. The O in CO means optional, she was a textile walking along the beach which was her right. Trouble is taking photos of people naked on the beach without their permission, well ..... You could argue that if a person gets nude at the beach then they are freely showing their body to anyone else at the beach, but I think photo's like this and your case are uninvited and not fair.