On the morning of August 21, 1968, as Soviet tanks rolled into Prague, a young photographer named Josef Koudelka began to take pictures, and he didn’t stop for the next week, as the people of the city resisted the occupiers.

Smuggled out of Czechoslovakia and published around the world — anonymously, in order to protect him and his family — Mr. Koudelka’s photographs became indelible images of the invasion and the Czech people’s bravery. Now, at a moment when the crisis in Georgia has drawn comparisons to earlier instances of Russian aggression, these photographs are getting a major exhibition in New York.

Beginning September 5, Aperture Gallery will exhibit around 70 large-scale ink-jet prints of Mr. Koudelka’s most iconic photographs. Aperture is also publishing the English-language version of a book, “Invasion 68: Prague,” which includes 250 images culled from Mr. Koudelka’s archives, many of them previously unknown.

At a press conference last week in Prague for the publication of the Czech version of the book and the opening of a related exhibition, Mr. Koudelka called the 1968 invasion “a tragedy,” but said that he was glad to have witnessed the extraordinary response.

Everything “changed at once, overnight,” Mr. Koudelka said, according to the Czech news Web site Aktuálně. “People began to behave to one another decently. Thieves declared that they would stop stealing since the police had more important things to do. Everything unbelievable was possible.”

At the time of the invasion, Mr. Koudelka was only 30. He had recently quit his job as an engineer to devote himself to photography, and had so far photographed primarily theater troupes and gypsies. On August 20, he had just returned to Prague from visiting gypsies in Romania.

In an interview in the fall issue of Aperture Magazine, Mr. Koudelka says that only after the crisis ended — on August 27, after the signing of the “Moscow Protocol,” in which Alexander Dubček and the other Czech leaders agreed to reinstate censorship and suppress reformist groups — did he develop the photographs he had taken during the week of the invasion. He left some of them with the photography historian Anna Fárová. She showed them to several people, including the curator of photography at the Smithsonian Institution, Eugene Ostroff, who brought the pictures back to America and showed them to the then president of Magnum Photos, Elliott Erwitt.

No one at Magnum had ever heard of Mr. Koudelka, Mr. Erwitt recalled in an interview with the Sun, but the photographs were remarkable. “I thought, ‘Wow, we must find a way to get this stuff out,'” he said. He asked Mr. Koudelka for the negatives, which various friends and contacts then managed to smuggle out of Czechoslovakia in their luggage.

The photographs appeared first in Look magazine, then in publications around the world. They were credited to an anonymous Czech photographer in order to avoid reprisals against Mr. Koudelka and his family. The Overseas Press Club awarded its 1969 Robert Capa Gold Medal, for best photojournalism requiring exceptional courage, to the anonymous photographer. Although he received asylum from England in 1970, only in 1984 did Mr. Koudelka publicly acknowledge having taken the famous pictures.

Even today, not all Czechs associate Mr. Koudelka’s name with the images. A sociologist at Charles University in Prague who was part of the underground during and after 1968, Jirina Siklova, said in an e-mail that she was familiar with some of the photographs, but she didn’t know that they were by Mr. Koudelka; she was under the impression that they were by either Jan Němec or Stanislav Milota, two Czech filmmakers.

For the book, Mr. Koudelka and a graphic designer, Aleš Najbrt, combed through Mr. Koudelka’s archive of almost 10,000 images of the invasion. They arranged the photographs they selected as nearly as possible in chronological order and interspersed them with primary texts, including radio broadcasts, statements by the Czech and Soviet governments, and eyewitness accounts. (Some of these texts, as well as a time line from the book of the events between August 20 and August 27, will be included in the Aperture show.)

Some of Mr. Koudelka’s photographs capture scenes of mayhem, such as the clash outside the Czechoslovak Radio building on the morning of August 21, when demonstrators set fire to tanks and 17 civilians died before soldiers occupied the building at 9 a.m. (In all, about 100 Czech civilians died during the invasion.)

Others document nonviolent expressions of resistance: tanks graffitied with swastikas, walls painted with anti-occupation slogans (“Killers, go home!”; “Socialism yes, occupation no!!!”), and graffiti of a swastika encased in a five-pointed star, referring to the five invading Warsaw Pact countries.

The recent Russian invasion of Georgia has reopened some wounds and provoked contradictory responses from the Czech government. The Foreign Ministry made an early statement supporting Georgia’s territorial integrity and sovereignty and indirectly blaming Russia for the conflict. Several days later, the Czech president, Václav Klaus, took an opposing view, telling Czech Radio that viewing the Russians as villains and the Georgians as victims was “a gross oversimplification,” and rejecting any analogy with 1968.

The exhibition at Aperture, which is co-produced by Magnum Photos, will run concurrently with another show at Pace/MacGill Gallery. The curator of the Aperture show, Melissa Harris, said that Mr. Koudelka, who lives in Paris and Prague and declined to be interviewed for this article, was initially hesitant to do the exhibition, because he is so involved in his current projects. At 70, he “has more energy than most 20-year-olds I know,” Ms. Harris said.

She said that using ink-jet prints was fitting for the journalistic nature of the photographs, and she, for one, did not hesitate to draw a comparison between history and today’s news. “Because of the sad events in Georgia, this becomes all the more relevant and resonant,” she said of the exhibition.

Quoted on the Czech news Web site Aktuálně, Mr. Koudelka said that, while his book is being published in nine editions, it will not be published in Russia. “There are publishers who are interested,” he said, “but they can’t come out with it. The political climate in Russia doesn’t allow it.”