In this undated photo provided by Christie's Images LTD, a 1972 painting entitled "Portrait of an Artist (Pool with Two Figures)," by British artist David Hockney is shown. The painting, considered one of Hockney's premier works, was sold at auction by Christie's in New York for $90.3 million. (David Hockney/Courtesy of Christie's Images LTD via AP)
David Hockney's 'Portrait of an Artist (Pool with Two Figures)' was sold at auction by Christie's in New York for $90.3 million. AP

'Salvator Mundi' and 'Rabbit': why are some people willing to spend so much money on art?