I'd like to know the answer to your question myself. I had enjoyed Wilson's covers since I was a kid (though at the time we fans didn't know his name). I remember being puzzled when this cover came out. GK covers were always bright and vibrant, but this looked like a grayscale drawing with color washed over it. Publisher's choice? Lousy separations?
May I be so bold as to ask where you got the picture of this original flash gordon 20 from? I have never seen a source for the painting? Thanks, Ashley Batchelor