I'm guessing this is on a trip around the three sacred peaks of Konka Risumgongba (modern day Yading). The European doesn't look like Rock - must be one of his infrequent companions/translators. They never lasted long.
Kham then and now. A photoblog showing how eastern Tibet looked in the 1920s and how the same places and people look now. Based on the explorations of botanist Joseph Rock.