Amazing Stories vol. 23, no. 8 (August 1949)
The title of the story clearly implies that she's dead? But she's upright still, although she's got an uncomfortable expression/posture and her clothes are falling off.
Perhaps he's saying "I paint from death!" to her right now and is just about to strike.
Original magazine: https://archive.org/details/Amazing_Stories_v23n08_1949-08_cape1736
@SFFMagazineCovers She’s not upright, that’s his painting on an easel. He’s looking down at her.
Not sure about the glass case (?) in front of him.
@JamesPadraicR
Oh I'm so dumb, of course that's it. He's looking back at her body over his shoulder, the way … no artist ever arranges his work and subject.
@SFFMagazineCovers
He reminds me of Raymond Burr, who played quite a few heavies in 40s and 50s.