Photography as an object of investment

[Galyona]

Here, for example, that sold at the December auction Shristies

1. ANSEL ADAMS (1902-1984)
    Mt. Williamson, Sierra Nevada from Manzanar, California, 1944
    Price Realized $ 17,500

2. ANSEL ADAMS (1902-1984)
     Special Edition of Fine Prints: Photographs of Yosemite
     Price Realized $ 40,000

3. BERENICE ABBOTT (1898-1991)
      New York at Night, 1932
      Price Realized $ 18,750

4. BERND & HILLA BECHER (1931-2007 & B. 1934)
      Grain Elevator, Broquiers, France, 2005
      Price Realized $ 15,000

5. IRVING PENN (b. 1917)
       Cretan Landscape, 1965
       Price Realized $ 13,750

How do you think these investments are justified?