If I buy an original work of art by a deceased artist, can I legally make prints for sale?

The copyright in a work grants several separate rights to the owner of the copyright. Mere ownership of a work does not give the owner of the work the right to reproduce that work. Since the artist in this case is deceased, you would need to contact owner of the copyright in the work of art (which may or may not be the heirs of the artist) to acquire the right to reproduce it. This presumes that the work of art is not old enough for the copyright in the work to have expired, for example, a work created in the 19th century or earlier, in which case you would be free to make copies.