In recent years, some fine art photography prints have sold for vast sums of money. Almost all of these valuable photographic prints were sold at Christie's and Sotheby's art auctions where the buyer, seller and price is revealed. One photographer appears on the top 10 list three times.
One particular outlier on this list would be Peter Lik; which some art publications have cast doubt as to the legitimacy of the sale because it was a private sale to an anonymous buyer. The news of the sale came via an artist press release. It’s not my place to judge here. I do not know these photographers personally so I’m just offering my observations based on what others including the New York Times have reported.
Sources: New York Times & Wikipedia
It's interesting to note how close in range the cost of these sales ended up at. I'm not an expert in how the exclusive art world works but I'm inclined to think that the pricing of this market is dictated by a small elite circle of institutions and buyers. The goal is not necessarily to purchase aesthetically-pleasing photography but more for bragging rights over edition sizes and one-upmanship. That side of the art world doesn't appeal to me in the slightest bit but to each his own. There is enough art in this world to suit art buyers from all walks of life. If you can afford multi-million dollar photography prints then more power to you. Another way to spend your fortune would be to buy out my entire photography archive. I might be biased but you'll get much more for your money by purchasing my work, literally. I'll even come personally meet with you and work out the terms of sale in-person. You could become the exclusive owner of my life's work for $12.5m.