I never thought of even asking a cemetery to take photos. I have some relatives at Mt Zion and was planning to visit - but thanks to the suggestion someone made, I did call them today. The cost is $15 per photo - you must mail a check and explain what you need, and include your email address for the photos.
A word of caution ... not specific to Mt Zion ... but I have heard people paying cemeteries for photos and they get useless photos. On another forum someone posted the photos she got from one of the area cemeteries which was a lovely photo of the bush that was totally blocking all but the very top edge of the stone, no writing visible at all. And what's worse the cemetery attached a bill for maintenance for the graves.