Unidentified – from Gravir?

This photo comes from Uig, where it was lying unidentified in the Comann Eachdraidh collection.  It’s marked on the back “M Campbell, Gravir” and there was a mark over the chap on the left.  But who was he, who are the others, what’s it doing in Uig and where was it taken?
Calum Macritchie believes that he is Murdo Campbell, brother of Mary Campbell, 13 Gravir, Mairi Dhomhnaill Ruaraidh who was married to a John Macdonald from Hacklete, Bernera.
Do you know any of the other people in the photograph?
Teen Anne from Uig has kindly solved the mystery as follows:-
“M Campbell was the late Maggie Campbell nee Saunders from 17 Valtos who married Norman Campbell who was missionary in Gravir.  Maggie supplied many of the Uig sheiling photographs in the CEU collection and I think everyone is from Uig. There should be a list of names, if not, I recognise most of them. Domhnall or Calum Beag a Creagain Mackay, 15 Valtos, Betsy Matheson nee Buchanan 7 Valtos, Catherine Smith 30 Valtos, not sure 3 Valtos or Christina Macleod 11 Valtos?, Bella Buchanan nee Smith 8 Valtos, Bell Bheag Mackay 9 Valtos and An “Eye Bheag” Buchanan 8 Valtos.”
Maggie Campbell is not in the photograph