Here's a great site for how to 'shoot' quilts. It's recommended by many quilt shows in their submission instructions.
http://www.hollyknott.com/stq/
I had an original design quilt custom longarmed by someone I had never used before. She did a beautiful job, I was very happy with it, and it was my plan to stay with her for a long time...until the day I visited her website. She posted photos of customer quilts, mine included, without asking the maker's permission, without mentioning the maker's name, without separating her own quilts from her customer's quilts. The implication was that they were all hers. Had I been asked, I would have gladly said 'sure' since it would be a plug for my design work along with her quilting, but she never bothered to ask. I never went back and I've obviously never forgotten why.
Please, ask permission before you use other people's quilts in promotional material for your business. It may not be 'legally required', but it's certainly the decent thing to do and it may just keep customers coming back to you. It can be as simple as putting a release on the contract/agreement you both sign when the quilt is brought in.