Xavier Di Petta and Chris Wild arrived at their vocation — as digital curators of historical pictures — in very different ways. For 18-year-old Mr Di Petta it was an outcome of a hobby that he fitted in around his schoolwork; for Mr Wild, 44, the route was more traditional. He had worked for a number of years in museum and photographic archives.

Curator used to be a rather rarefied tag, applied to specialists who preserved artefacts and organised collections. In the digital era it has become a catch-all term for anyone who aggregates and selects content. Anyone creating an iTunes playlist could be called a curator. This democratisation suits Mr Wild, who insists cultural institutions should not be precious. “We are all casual curators when choosing and showing things to other people. It’s a gradient.”

Originally from Shepparton, Australia, Mr Di Petta’s path into archive curation was accidental. In July 2013, aged 16, he set up a Twitter account with his friend Kyle Cameron, a student from Hawaii — the pair had met through a YouTube partnership programme. The two had already created @EarthPix which posts pictures from towns and forests around the world, and wanted to see how historical pictures would fare. The first post was the Depression-era photo of New York construction workers lunching on a crossbeam hundreds of feet in the air. “I was surprised by how many times it was retweeted,” says Mr Di Petta. Two years later the @HistoryInPics account has over 2m followers and legions of copycats. Mr Di Petta shrugs off the competition. “It’s the way it is. I don’t care.”