In response, the agency behind the poster argued the image had already been widely viewed across the world and featured on the front page of newspapers. It said the photo was also used in promotions for the exhibition in 100 cities and 45 countries around the world.
"We did not select this photo with any intent to promote indecency, offensiveness, violence or a disregard for safety. It was selected because it is the winning exhibition image," the agency said.
Most of the complaints board did not accept that the advertisement could lend support to violent behaviour and felt it "was unlikely to cause serious and widespread offence".
A minority argued the poster was in fact likely to cause serious and widespread offence, and "more care should have been taken to ensure it was not exposed to such a wide audience considering the graphic, real-life violence".
The majority ruling meant the complaint against the advertisement was not upheld.