One such prominent collector is Bernard Mahé, a French former investment banker who six years ago opened Gallerie du 9éme Art in Paris, devoted solely to comic art. "It's a new generation," says the 51-year-old Mahé, who has the world's largest collection of strip art—early 20th-century newspaper "funnies" such as Winsor McCay's Little Nemo or George Herriman's Krazy Kat. "The old generation collected comic books but the new generation collect the art for art's sake."

Like comic books, original comic art was once considered ephemeral, if not out-and-out trash—publishers used to throw the stuff away. By the mid-'60s, publishers started allowing artists to keep their original drawings and collectors began coveting work from the medium's best, like Steve Ditko, whose idiosyncratic drawings brought Spider-Man to life; or John Buscema, best known for his muscular renderings of Thor and Conan the Barbarian; and the undisputed "King of Comics" Jack Kirby, who with Stan Lee created the Fantastic Four, the X-Men, and just about every classic character in the Marvel pantheon. Soon, collectors coveted comic art in all its forms. By the early '90s both Christie's and Sotheby's were auctioning comics along with other collectibles. And as comics gained respectability, the demand for such art just kept growing.

Original black-and-white panel art is more valuable to collectors than comic books. Even the most collectible titles—say, a near-mint condition of Amazing Fantasy No.15 from 1962, in which Spider-Man first appeared—can sell for approximately $75,000. But at the end of the day it's still "a machine-reproduced artifact," says Douglas Wolk, author of Reading Comics, and while rare, hardly unique. The original art for the same issue would be worth far more on the open market—if it were available. Earlier this year, an anonymous collector donated the art for Amazing Fantasy No. 15 to the Library of Congress.

In some European countries, like France, which has a rich comic culture of its own, American comic artists are held in especially high regard. The French, says Mahé, embrace comic artists in sort of the same way they love Woody Allen and Jerry Lewis. "In France, people see the art and recognize the artists," he says.

And they're willing to pay for it too. A 1932 oil painting of Tintin by Belgian artist Hergé sold at a Paris auction in March for $1.3 million (or €764,200), a watershed moment in the original comic art market. "It is by far the highest price paid for any piece of original comic art," says Mannarino, who notes that the largest collection of Jack Kirby Fantastic Four artwork resides in Paris. In fact, Mannarino does so much business in the City of Lights that he bought an apartment there—paying for it in cash and 40 original comic strips of Terry and the Pirates from the 1930s, worth an estimated $40,000.

Which doesn't help Americans like Tim Soter, 37, a Brooklyn-based freelance photographer with a small but eclectic collection. "It's a good time for comics but a bad time to collect comic art if you're an American collector," he says. "The dollar is not strong and it's basically a two-for-one deal for the Europeans. You really have to love the piece twice as much as they do to spend your money."