This is the original preliminary painting created for the novel by Richard Matheson, described as "an erotic ghost story" published by Tor, 1994 (I show the cover for reference)  if you look closely, this prelim is very much like the cover art and interestingly, one of the few "gothics" I've ever seen by DKS.  It's one of the larger ones, too.... nicely done in acrylics on illustration board, 7.5" x 5"  and is titled, signed and dated 1993 on the reverse.