Taking pictures and photos in the naturism resort is not a good idea i.e. you should not sit on the beach taking photos of other naturists and if you do you might well find yourself in trouble with the police there. You quite likely will also find yourself on the wrong side of other tourists there.
You do see people take a camera with them in the resort now and again but the idea is that you only take a picture of yourself or partner and if you were ever to take a photo of others, you should ensure that you have the permission of anyone in the photo.
Overall, you are best off enjoying everything Cap d’Agde has to offer and leaving the camera in the hotel, tent or apartments room.
You can also learn more about Agde and Beziers online with the local tourism site on the area.
For some more useful information on visiting the resort