Photography's place in the art market

Interesting article in the NY Times today about the rise of photography as a valued collectable and the variations in pricing as the medium matures. The article claims Man Ray's "Glass Tears" as the most expensive single photograph ever sold, a private sale for $1.3 million. I think the previous record was for a daguerreotype of a greek ruin for something like $900k at Christie's (though that may only be an auction record.) The article is peppered with wry comments like this one:

Rick Wester, director of photography worldwide for Phillips, de Pury & Company, observed ruefully: "You can buy the best Robert Frank you can find for half of what you can expect to pay for an Andreas Gursky at auction. Frank is among the most important artists of the 20th century. Anyone looking for the logic to that will end up mumbling to himself over a bottle of scotch for years to come."