You find many renderings of John Martin‘s The Bard in the Internet. I think that in this comparison the left one is the right one and that <! https://twitter.com/Elizabethyha/status/1084085736620605440>the right one is not John Martin’s.
In Henry Holiday’s illustrations to Lewis Carroll’s The Hunting of the Snark there are several references to John Martin’s original painting. Some are funny, some are spooky.
2018-10-24, update: 2019-02-09