AMSTERDAM -- A haunting image of migrants passing a baby underneath a razor-wire fence on the Serbian-Hungarian border won the prestigious World Press Photo award for 2015 on Thursday -- even though it had never been published.

Australian freelance photographer Warren Richardson made the moonlit image on Aug. 28 and said he offered it to two news organizations, neither of which responded.

Jury members, however, saw something special in the black-and-white image. Vaughn Wallace, deputy photo editor for Al Jazeera America, said the image is "incredibly powerful visually, but it's also very nuanced."

The photo, he said, "causes you to stop and consider the man's face, consider the child. You see the sharpness of the barbed wire and the hands reaching out from the darkness."

Richardson said he did not carry any equipment to transmit his images while he spent days camping near the Hungarian border crossing at Roszke to document the passage of the migrants fleeing conflict, poverty and persecution in the Middle East and Africa. He said the delay in sending out his images from his home in Budapest may have been to blame for the lack of interest.

"Sometimes, it's first in, first served, and I understand that theory," he said. "I can't blame anyone else but myself. But at the end of the day the picture talks for itself."

"I would have thought straight away, 'Yeah, this will definitely be published,"' he said. "But I didn't think like this."

It was so dark when he took the picture that Richardson did not even realize the migrants were passing a baby under the fence until he looked at the image on his computer. He checked the photos only once he got home to preserve his camera's battery.

"Had I used a flash, I would have given their position away to the Hungarian police," Richardson said.

The image won top prize in the contest, which drew 82,951 images from 5,775 photographers. It also won the Spot News Singles category.

Last year's competition was overshadowed by the disqualification of a winner who admitted that one in a series of pictures about the Belgian city of Charleroi was actually taken in Brussels, and by controversy surrounding the pictures of the gritty, post-industrial Charleroi.

Lars Boering, managing director of the World Press Photo Foundation, said the contest set up a new code of ethics for this year's contest to ensure the integrity of images. He praised photographers for largely sticking to it, saying there were more checks and "fewer problems" than last year.

"We see that the photographers are as committed as we are to providing accurate and fair images on the world's most important events and issues," he said.

Several winners in the news categories focused on the migrant crisis and one of its root causes, the devastating civil war in Syria.

But the contest's wide range of categories also provided an eclectic mix of other subjects ranging from wrestlers in Senegal to ice hockey players in Russia, and from people diving with whales to orangutans climbing trees.

Japanese photographer Kazuma Obara won the People Stories category for a series of pictures shot on old Ukrainian film depicting the life of a woman affected by radiation from the Chornobyl nuclear disaster. Associated Press photographer Daniel Ochoa de Olza won second place for portraits of young Spanish girls sitting in decorated altars as part of a festival. Ochoa also took third place for photos showing raindrops covering portraits of victims of the Nov. 13 Paris attacks that were left at a street memorial.

Americans swept the top three places in the long-term projects category. Mary F. Calvert won for a series of photos dealing with sexual assault in the American military. Nancy Borowick took second place for a series of photos documenting her parents' battle with cancer. And David Guttenfelder was awarded third place for a series of pictures from North Korea, the bulk of which were made when he was a regular visitor to that country as a staff photographer for The Associated Press.

The New York Times won three categories -- General News Singles, General News Stories and Daily Life Stories -- and Times photographers placed third in General News Stories and second in Daily Life Singles. French agency Agence France-Presse won the three top placings in Spot News Stories and a second place in General News.