I've been moving through the DC/Vertigo trade Swamp Thing: Dark Genesis, which collects all ten of the issues drawn by Bernie Wrightson and written by Len Wein, along with the first appearance of Swamp Thing from House of Mystery, and it's obviously a classic.
Frankly, before reading some Swamp Thing, I wasn't exactly sure what the fuss was about. Wrightson's work seemed really cool and impressive, but had always had this background as like one of the guys and in terms of comics history, comics discussion, etc. This had the odd effect of distancing his work from its context and focusing not on his comics drawing or his pencils but his illustration.
I had the fortune to see him speak as a guest of honor at the Baltimore Comic-Con this past fall, along with Jose Villarubia, and he came off as this incredibly modest, hard-working, auto-didact guy who more than once was basically like, "Hey, I just like to draw scary monsters and gore." It seemed an odd contrast to his reputation, work like his serious critic-bait Frankenstein book (that just got a nice re-release), and especially a slide-show to Wrightson's right isolating particularly Wow!-ish panels and trying to turn them into conventional visual art.
Like people who say rap or Bob Dylan lyrics are poetry, trying to frame Wrightson's work as Art is a disservice to his work and comics art in general. It simply is what it is and does certain things better and more effectively than say, Goya or whoever else you want to name could ever do it. One imagined those that put that slide-show together or the next author to write a "take comics serious" book scouring the Swamp Thing trade for particularly beautiful or compositionally brilliant pieces, when it's better and probably even necessary to scan the whole page or the whole damn book.
Pragmatically, choosing an illustration to represent the work just makes sense, but there's something that even us obsessive comic readers do with our eyes when we look and judge comics art. Our eyes shift away from the progression of panels, the visual narrative and try to spot that single, awesome or beautiful or just plain cool composition and it's something of a problem, I think.