A shoe box full of images capturing life in India at least a century ago has been discovered in one of Scotland's national collections.
One shows buildings in the city of Calcutta lit up over the Lal Dighi body of water, commemorating a British royal visit, while another depicts ships arriving at the Chandpal Ghat, the main landing site for visitors to the city along the Hooghly River.
All 178 of the plate-glass negatives were found inside a size-nine Peter Lord shoe box by the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) in Edinburgh.
They are said to have been taken in the country at the time of the British Raj and it is thought the negatives were untouched for almost 100 years.
Archivists at RCAHMS have already confirmed that some of the images were definitely taken in 1912, when King George V and Queen Mary visited Calcutta. It was the only visit by a British monarch to India as Emperor of the subcontinent.
Some of the photographs show the city's buildings lit up at night in tribute to the royal visit.
Little else else is known about the images and the photographer, prompting a search for clues as to his or her identity.
One theory is that the photographer was a British civil servant in Calcutta, or was connected to the jute trade, as many Scots were said to be at the time.
There is a Scottish cemetery in the city that dates back to the time of the British Raj, which has recently been cleaned up and recorded.
RCAHMS hopes that members of the public and photography enthusiasts might be able to shed more light on this discovery.
They also approached John Falconer, curator of photographs at the British Library, who helped to identify some of the locations and remarked on the high quality and beauty of the images, but so far the identity of the photographer remains a mystery.
Claire Sorensen, RCAHMS architectural historian, said: "We don't know for sure how they came to be in our collection because we receive archive material from countless different sources, ranging from the archives kept by architectural practices to generous public donations.
"Sometimes we take in large amounts of material at once, and often documentation for historical deposits does not exist.
"Over time all this new material will be inspected and catalogued as part of our collection - undergoing conservation work where necessary - and then made available to the public.
"It's fantastic that a small shoe box contained such a treasure-trove of photographic imagery, but in some ways it's not unusual.
"Our experience as an archive has shown us that some of the most interesting discoveries can be made in the most unlikely of places."