If you took the photo originally and did not take a photo of someone else’s photo, then you own the copyright rights in that picture. If the facts are: You created the photograph and sold a copy to someone else then, yes, they can resell or give away that actual copy. It is like when you buy a book.
What Sells Best On Shutterstock?
Some types of photos that sell best are Portrait Photography, Food Photography, Landscapes (usually with people) and fine art photography (artsy).