Debby,
While there are others here much more qualified to answer, it is my belief that the only time you need the artist's permission to resell (or remove) a work of art is when it is in the public domain, or when there is a binding agreement between the parties that prohibits a sale without consent. I do believe that it would be an infringment if the buyer were to make copies of the art work and sell them for profit, but using photographic facimiles of the original to aid in its resale would be allowed.

Once again, I am not a copywrite attorney, and could be COMPLETELY wrong.

Jim in San Diego