Billy the Kid, the Wild West gunslinger, is usually associated with a Colt single-action 44, not the genteel elegance of a varnished oak croquet mallet.
However, a photograph of the legendary outlaw leaning on a croquet mallet has emerged - only the second known photo of "The Kid", whose real name was Henry McCarty.
The photo shows McCarty playing croquet with his gang of Lincoln County Regulators in 1878.
It was bought by collector Randy Guijarro for US$2 ($3) from a Californian junk shop in 2010 and will now be sold by Kagin's auctioneers for an estimated US$5 million.
"When we first saw the photograph, we were understandably sceptical - an original Billy the Kid photo is the holy grail of Western Americana," said Kagin's David McCarthy. "A team of experts had to be assembled to address each and every detail in the photo to ensure that nothing was out of place." The only other known photograph of McCarty was sold for 1.4 million ($3.2 million) in June 2011.
The Kid was shot dead at age 22 by lawman Pat Garrett in 1881.
