This image probably came as much of a surprise to me as it did to you, except I saw it several weeks earlier than you. I commissioned a "variant cover" from Darwyn Cooke, and I guess I was expecting something celebratory for the 50th issue of Justice Society of America. If memory serves me, and there's no reason why it should anymore, a celebratory cover of a completely different sort showed up, in full color, without any kind of preliminary. We all trusted Darwyn that way, and I was happy to have this. And I eventually got my "celebratory" cover for the final issue.
It must have taken some doing for Darwyn to overcome the resistance that comes of having a style that is more associated with animation than mainstream superhero comics. It's a tribute to his graphic ingenuity that he could win over people who expected something more conventional.
The very best thing I can say about Darwyn is that he showed everybody how it's done.

