Looking through a school book about World War One, former teacher Kathryn Robyns was surprised to see her grandfather among the images from 1917.
William Ensor did not talk much about his service but he featured in photos which became iconic among war records.
"My grandfather was a hero to us - not because of his service but because he was extraordinarily kind," she said.
Ms Robyns, from Anglesey, was thumbing through books at Ysgol Uwchradd Bodedern when she spotted her grandfather among the soldiers at Ypres.
The image was taken by Lt John Warwick Brooke, an official photographer for the British Army, on 1 August 1917, during the campaign which became known for the scale of casualties.
The photograph has since been digitally coloured by the Imperial War Museums.
Ms Robyns' grandfather, who was also from Anglesey, enlisted in January 1915 and, after completing basic first aid training in Prestatyn, Denbighshire, he was sent to the Western Front.
"I realised immediately that my grandfather was in the picture," she said.
"He always said that he didn't want to go to war to kill, and the best way he could help the cause was to go as a stretcher bearer.
The Armistice 100 years on
Long read: The forgotten female soldier on the forgotten frontline
Video: War footage brought alive in colour
Interactive: What would you have done between 1914 and 1918?
Living history: Why 'indecent' Armistice Day parties ended
"He never talked much about the war, but I do remember that every year on Armistice Day, he would crave company and I'd sit with him then many times," said Ms Robyns in an interview with BBC Radio Cymru's Post Cyntaf programme on Wednesday.
"The one thing he would say that hit him most was losing friends."
Mr Ensor survived the war and worked as a surveyor. He died at the age of 83 in 1969.