Thank you for the replies, but it just makes it more mysterious why these photos are in my mother's very small collection of family photos.
The only Walters connected with my family that I have come across so far are a Walter Stirrup born in 1865, who was a nephew to my great great grandfather William Stirrup, and that Walter's son, Walter Cunliffe Stirrup who was born in 1890. Try as I might, I can't make the name on the back of the photo match either of those 2 Walters!
I can't find any connection with the name Gilbert, Gilchrist or Gildnel.
As far as the Walter Geldart who married Janet Boyle are concerned: Walter's grandfather apparently was a boot and shoe maker in Blackburn, as was my great great grandfather William. Walter's birth in 1876 would make him a contemporary of William's children. Perhaps he was a friend of my great grandfather Reginald but if he was that good a friend as to send back photos from India you'd think that Reginald would at least know what his wife's name was, even if he hadn't met her. With Janet, her mother's maiden name was Haworth. William Stirrup's mother had a sister Jane who married a Thomas Howarth, and on a quick back check Jane is possibly Janet's great great grandmother.
So the who and the where may have been discovered, but now the question is why these photos have been kept and passed on in a very small bundle of family photos when the link appears to be very remote, when there are no photos of close relatives.
Cathryn