This was a curious gesture. Granny was in her locally woven traditional fabric, hanging around with the grandkids. This bunch of foreigners turned up (minded, of course, by local Party officials). We asked by gesture if we could take photos, got agreement, and Granny saluted as part of the image-taking. I think perhaps in the past, a photo always needed to be accompanied by a gesture of support for officialdom? I don't know, of course, and can only conjecture.
Of course, the grandkid had to do a mug shot over Granny's shoulder.