Reader Chris de la Rosa has pointed me towards a comics adaptation of Clark Ashton Smith's "The Vaults of Yoh-Vombis" by famed Heavy Metal artist Richard Corben. It's actually pretty good, although I hope I can be forgiven if I quibble over the presentation of the Martian Aihais, who don't bear a lot of resemblance to Smith's description of them. Likewise, I think the comic, while faithful to characterizations and events of the short story, lacks some of the terrifying punch of its inspiration, in part because words, particularly those of an author as talented as CAS, are better at evoking certain emotions than are illustrations.
That said, it's a good adaptation nonetheless and well worth a look if you've already read the short story. I wouldn't recommend it to complete neophytes, though. Read Smith's work first, lest the comic spoil your enjoyment of it.