We are a small Museum and have not had this problem yet, but I’m sure it will become more common as you suggest. I’ll be curious what others have to say. We do not have a clause in our incoming loan agreement either.
My gut feeling would be to deleted the digital copy of the artwork at the conclusion of the exhibition (Delete it from the “trash” folder too). You also have to consider the possibility that someone may have copied the digital image and saved it with a different filename. At the conclusion of a normal loan, an item is returned; it would not be in your possession any more. This is why I would delete a digital loan. Just before deleting, I would confer with the artist. The artist may have lost his or her digital file.
The artist may have included an unprintable “digital fingerprint” in the image that was unique to the file (s)he sent you. You would not want the artwork to leak out if your digital copy suddenly appears on-line elsewhere. Outside of our Museum, my full time job for many years has been in computer programming, system analyst and database work.
David Cranston, Curator
52 Main St – PO Box 275
Lake Luzerne, NY 12846-0275