I took alot of photos of the girls on my recent first trip. Most were happy to pose with clothes, some in underwear but they are generally shy about nudity.
"YOU TAKE PHOTO!
she yelled as she grabbed the camera off the table....I took it and made a lame attempt to act like something was wrong with it
then I put it away and then she chilled out.... I was lucky have read stories where they lose it and start breaking things....
Best to ask permission and pay the extra baht if she is agreeable