The man famously pictured as a boy wearing a gas mask and holding a petrol bomb during the Battle of the Bogside personified the fight for civil rights, according to one of the leaders of the movement.
Paddy Coyle from Londonderry, who died at the weekend, was just 13 when the snap was taken by photographer Clive Limpkin in 1969, who passed away in May.
The image made front pages across the globe after it was taken during the three days of rioting in Derry, viewed by many as the beginning of the Troubles.
Mr Coyle's cousin, Bogside artist Tom Kelly, said he passed away on Saturday.
Derry City and Strabane councillor Eamonn McCann, who was one of the civil rights protest leaders in the city on the day the photo was taken, believes the image is one of a few that is recognisable far outside the island of Ireland.
In a social media post Mr Kelly, who later used the image in one of Derry's murals, said: "Paddy never exploited his iconic image. He refused many offers from TV documentary makers and newspapers to tell his story behind the image as he didn't like talking about it."
He added that Mr Coyle will be "missed by all who knew and loved him, but his image as a young boy… in 1969 will live on forever".
Mr Limpkin described the photograph as the nearest thing he "ever had to an iconic picture", and Mr McCann said he couldn't disagree.
"It was a mass struggle and you can see that in the picture," he added. "Paddy Coyle represented a whole lot of people in a whole lot of places at the time.
"Civil rights was against oppression, for a fair voting system and against discrimination. These are all civil rights demands and they're not specific to Ireland at all. That's why that photograph has gone all around the world. It ended up on T-shirts, tea towels, postcards and so forth. Paddy never got any money for these, and he didn't ask for it either.
"Never was an image of a man more widely distributed without any attribution or acknowledgement, and he didn't seek to be acknowledged, so that's fair enough." Mr McCann added that the photo was one of the defining images of the Troubles "without any doubt".
"It's to do with the period of the Troubles and the fight for democracy and against sectarianism rather than what came later," he said.
"In 1969 and what was happening in Northern Ireland was widely seen, and rightly seen, in the context of all the other struggles going on in the world.
"The Americans were against the Vietnam War and so forth. At that time with what was happening in Derry and Belfast could be seen, and was seen by some people, as part and parcel of what was happening globally and not just our own struggle for 'Irish freedom'. It was freedom for everybody against the oppression for a fair voting system, fair electoral rolls and so forth."