The picture 'Rhein II' by german visual artist Andreas Gursky has become the most expensive photograph in the world after being sold for $4.3 million at Christie's in 2011. The previous record was for the picture "Untitled #96' by Cindy Sherman, with a value of $3.89 million.
Gursky's picture is an image of the river Rhine and has a size of 151 x 81 inches (380 x 210 cm.).
For more info about this picture:
en.wikipedia.org/wiki/Rhein_II