Well, let's see.
My oldest son's mom allowed me to take pics of her when I was able to borrow an early digital camera from the retail store I worked at. But she wasn't very prudish at all.
My ex let me take pics and video without question. I just said, "hey, this might be fun" and she said, "definitely!"
My wife is even further from the prude end of the scale (hence the Exhibition shots) and I think if I went too long WITHOUT taking nekkid pics of her, she might think I didn't want her anymore :-p
So, it's hard for me to personally give advice if she really is a bit prudish. However, with the first two mentioned above, I was instrumental (thank you very much) in bringing their sexuality around quite a bit. *shrug* midas touch? j/k Sometimes you just have to make them want it. Tease her and flirt with her when you can't get freaky. Kiss her neck, hold her hand, love on her constantly so that when you two do get home and ready for "the deed" she's already as ready as ever. Then introduce some new ideas, slowly. Eventually she may realize that prudism isn't all it's cracked up to be.
