In mythology, Pygmalion is a sculptor who falls in love with his statue of a beautiful woman, which comes to life.
The idea has inspired many other works, including "My Fair Lady," a scene in Shakespeare's "A Winter's Tale," and an episode of the Twilight Zone that I saw recently on the SciFi channel, "A World of His Own" (1960). In the "Twilight Zone" episode (which is excellent) a playwright, played by Keenan Wynn, has his creation, a lovely young woman, come to life.
In "Dark Shadows," Charles Delaware Tate has similar powers - Olivia Corey began life as a painting (if I remember correctly). I used to be very impressed by how widely read the DS writers seemed to be. Stepping back just a little from that view now, I wonder if they simply came up with this concept from seeing the "Twilight Zone" episode.
OK, I won't go that far. The DS writers do seem to have been well read. In this case, though, it seems possible that someone on the DS creative team might have had their memory of the Pygmalion story jogged by seeing the "Twilight Zone" episode, and then thought the same thing could work on DS - which it did.