Billy the Kid Image Fetches $2.3 Million at Auction in Denver

VIDEO: New Mexico to Pardon Billy the Kid?

One of the last surviving images of Billy the Kid fetched more than $2 million at an auction in Denver this weekend.

The portrait of the infamous outlaw was sold to private collector William Koch for $2.3 million at Brian Lebel's 22nd Annual Old West Show & Auction on Saturday, the Associated Press reported.

"I love the Old West," Koch told the Denver Post. "I plan on enjoying it and discreetly sharing it. I think I'll display it in a few small museums."

Auction organizers originally estimated the picture would bring in about $300,000 to $400,000.

The tintype image shows Billy the Kid with a holstered Colt pistol and wearing a black hat.

According to legend, Billy killed anywhere from eight to 22 people.

The picture was believed to have been taken in Fort Sumner, N.M. during 1879 or 1880.

It is reportedly the only authenticated, surviving image of the outlaw.

"There's only one photo of Billy the Kid, and I think that's why it captivates people's imagination," auction spokeswoman Melissa McCracken told the Associated Press before the auction.

ABC News' Jessica Hopper contributed to this report.