I'm a bit familiar with CC by SA which is why I bring this up.In particular he has done none of the following:
Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made.
I'm also fairly sure its also not printed under CC by SA as its only listed as "All Rights Reserved" in the books front pages. Use of the image can be found in the section concerning the Flat Earth Bible.
I'm asking more as an effort to let you guys know. That, and if it Dubay's book was indeed share-alike we'd love to include it in our library. This looks to me like just unlicensed use of the image though.