It's nice when I agree with Lawyers, otherwise I say well that's what lawyers are for is to present opposing sides.
In this case the painting was the original work, you could run into issues if you exhibited it (and you will notice in some TV home shows how they blur the artwork), and then there was a photo of the picture (I don't know if it was taken by someone else or not) which again should be referenced, and then there was a quilt. The quilt is its own object, it is not the same media as either of the previous forms. And, as QuiltingLawyer said, it is a useful object and so especially not protected.
I started working at a large advertising agency where I had to deal with many copyright issues. You know how sometimes if you ask for a "coke" and they say "we have Pepsi" that's because the agency I worked for had the Coca Cola account (and Loreal and others you know), and periodically they would send us out as secret agents and deliberately ask for a Coke at a Pepsi place and report back what happened. Some brands are vigilant about copyright protection because words become common use. Bandaid is a brand name. They will get you in a tv show, movie, or print at if you are using a bandage and calling it a Bandaid. Kitty Litter is another brand name trying hard not to become generic. "Cat Box Filler" is the actual term.
It is fair personal use for you to make a direct lift of someone else's quilt down to the same fabrics even, if you make no changes, you can even quilt it the same. Basically, if you can design it you can make it and once you make it you can show it. I wouldn't show such a thing as an original work but I have no problems crediting the designed. Some organizations may have rules for attribution if you show it. I personally believe in attribution in addition to copyright protections, they are separate but related issues.
We are discussing some of these issues in this thread and it is a good discussion for quilters to have, when does something become "yours":
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