A picture by the photographer John Thomas, who travelled Wales by horse and cart capturing everyday 1800s life, has been found on the Llyn peninsula.
Few people have previously seen the picture of cobblers in Pensarn
According to expert William Troughton, John Thomas' work is important because it showed how people really lived.
The photo of cobblers in Pensarn on the Llyn had previously been unknown.
The photograph was discovered after a woman from Aberdaron lent the local history website Rhiw.com a collection of old pictures.
The National Library of Wales has a collection of more than 3,000 of his negatives bought by Sir O M Edwards.
Gwenllian and Tony Jones realised the significance of the photograph after spotting part of a stamp with Thomas, 47 Everton Road, Liverpool - the address of the Cambrian Gallery - on the back.
Experts at the National Library in Aberystwyth then confirmed the find was a photograph by John Thomas, probably taken between 1880 and 1890.
"There is a real wow factor to this discovery, especially when we realised it was not in the collection of his work held at the national library," said Gwenllian Jones.
"We are just so pleased that we have been lent this picture, as hardly anyone else has seen it," Mrs Jones added.
"It is always interesting when his photographs turn up.
"They don't have monetary value, yet they are very important showing us the tools people used and the clothes they wore for their work," said Mr Troughton, visual images librarian at the library.
Forced to retrain
Mr Troughton said Mr Thomas' work was extraordinary because he travelled all over Wales at a time when many roads were little more than tracks.
"He travelled around Wales by horse and cart and had to develop his photographs wherever he was. He couldn't just pop his work down to Boots when he got back," said Mr Troughton.
Originally from Llandysul in Ceredigion, Mr Thomas worked in a draper's shop in Liverpool until he was forced to retrain as a photographer because of ill health.
In his diaries Mr Thomas noted that he tried to arrive at a factory or workplace at about noon to make sure he had the best light, to make sure the workers were on their lunch break, and so that he did not upset employers by taking up work time.