I've noticed in most ladies pictures I don't see any jewelry. Wondering is jewelry a good gift or is that something a lady/provider would prefer to pick out herself?

I like unique pieces so I would prefer to buy it myself. I only wear silver jewelry too. Some people wear gold only and some both, just based on their personal preferences. Maybe take her with you or give her a gift card to purchase something that she likes. I had a client who sent me a couple of different pictures of watches that he wanted to buy me for my birthday. I didn’t like any of them. I told him it’s not easy for me to even find a jewelry pieces on my own, but as luck would have it I had, had my eye on a watch that I wanted and he just sent me the money and I bought it and at least it was something I wanted and he was happy to have done it that way. Nothing like getting a gift you don’t like and won’t wear.

In professional photographs, jewelry is generally discouraged for a number of reasons. It takes attention away from the person’s face or body and also sometimes causes reflections, camera flares, etc. Usually, ladies will wear accessories to compliment the “look” she’s going for, but less is more. There are obviously exceptions to this, though.  
If you want to look for indicators as to what a peovider’s Taste in jewelry would be, might be best to look at non-professional photos, like selfies. Lots of girls post selfies on a twitter (my handle is @priyarainelle - shameless plug)

Jewelry is always a good gift but if you don't know her well (like sensitivities to certain metals) then a gift certificate never hurt either.  

I rather use it on my personal life.  
Mainly I always wear Tiffany & Co. and with a casual look I threw a Alex & Ani piece ussually a quartz or different stones. It depends of what I am wearing; but for photoshoots I rather keep it simple as well.