maternity photo payment advice (SIL)

Nicole • Mama to Matilda + Betty 💕

My sister-in-law spent about 3 hours last night taking maternity pictures of me and my husband. She has a really nice camera that she uses for fun, and we’re her first maternity picture experience. I know we for sure want to compensate her, but I’m not sure on how- like, just cash (how much?), a more thoughtful gift (also clueless on that), etc.? Of course she said, “I don’t want anything!” but that’s not happening lol. All advice appreciated 😊