(CNN) -- The photographer who snapped the now-famous image of a man about to be struck by a New York subway train is defending himself against critics who say he should have helped, as controversy also rages over the New York Post's decision to publish the picture.
Freelance photographer R. Umar Abbasi's image shows 58-year-old Ki-Suck Han desperately clawing at a New York Square subway platform after being shoved onto the tracks by a man with whom he had been arguing.
Seconds after Abbasi captured the shot -- accidentally, in an effort to warn the train conductor, he says -- the train struck Han. He died at a hospital.
Police said Wednesday they had arrested a homeless man, Naeem Davis, 30, on murder charges.
In his Wednesday piece for the Post, Abbasi said people who've criticized him for the shot have no idea what they're talking about.
"I had no idea what I was shooting. I'm not even sure it was registering with me what was happening. I was just looking at that train coming," Abbasi said in the piece.
He said he was trying to get the train operator to slow down by furiously firing off his camera flash.
Abbasi said he didn't look at the pictures before returning to the office and turning his camera's memory card over to police. The Post published them the next day.
"Doomed" the headline screamed. "Pushed on the subway track, this man is about to die."
Readers and media critics quickly jumped on the newspaper's decision to use the image. On Twitter, users posted that it was cruel and "snuff porn."
Lauren Ashburn, a media critic and editor in chief of the website Dailydownload.com, called it "profit-motive journalism at its worst."
"It's insensitive, it's inappropriate, it's sickening rubbernecking," she said Wednesday.
But Howard Kurtz, host of CNN's "Reliable Sources" and the Washington bureau chief for The Daily Beast and Newsweek, said he sees an argument for publishing the image.
"Because this is every New Yorker's nightmare," he said.
"I do still wonder why the photographer's first instinct was to take pictures," he said. "I do wonder that."
Jeff Sonderman, a fellow at the journalism think tank Poynter Institute, wrote on the organization's website that it appeared journalists were largely critical of the decision.
"Even if you accept that that photographer and other bystanders did everything they could to try to save the man, it's a separate question of what the Post should have done with that photo," he wrote. "All journalists we've seen talking about it online concluded the Post was wrong to use the photo, especially on its front page."
Kenny Irby, a senior faculty member for visual journalism and diversity programs at Poynter, said Tuesday that what the paper did wasn't necessarily wrong.
"It was not illegal or unethical given that ethical guidelines and recommendations are not absolute," he said in an e-mail. But he also said the Post should have used another image.
"This moment was such for me -- it was too private in my view," he wrote. "I am all for maximizing truth telling, while minimizing harm, which can be done by fully vetting the alternatives available and publishing with a sense of compassion and respect."
The Post is no stranger to walking up to the lines of journalistic ethics -- and sometimes crossing them -- with its pithy, often lurid, coverage of crime and other news in the Big Apple.
"HEADLESS BODY IN TOPLESS BAR," the newspaper once famously shouted from its cover.
Nor is the Post shot the first news photo to generate ethics concerns.
An Agence France-Presse photo that won the 2012 Pulitzer Prize generated controversy for its depiction of a girl in Afghanistan crying amid a number of bloody bodies.
Also this year, the New York Times published a graphic image showing blood streaming from the body of a victim after a fatal August shooting at the Empire State Building.
At the time, Poynter quoted a Times spokeswoman as saying the image was "a newsworthy photograph that shows the result and impact of a public act of violence."