The first reprint (since its original publication in 1927) of The Dark Chamber was in mass market form by Popular Library of New York. Though undated, it came out in October 1972. Here is the cover:
There is no credit for the cover art, but it's style looks somewhat familiar. Anyone have any theories about who the artist was?
Interestingly, the same art was used on the German translation of John Crawford's Dark Legion (1967), when it was translated into German in 1973 as Der Geisterhügel. (John Crawford was a pen-name of John S. Glasby, 1928-2011.) It has been suggested that the art is by UK artist Bruce Pennington, but Pennington himself has said it is not his work. Since the first usage of the art was on a US cover, one would suspect it was a US based artist.