Photograph of boy standing by threshing machine

Having found a mysterious letter in a secondhand book (see another web page on this site), many years later I bought a secondhand book that also had something unexpected in it, the photograph above

It shows a threshing machine driven by an engine on the ground out of sight on the left. A worker appears to be manoeuvring a loaded sack of grain on to a weighing scales. Perhaps the scales clanged as he was doing it and the boy turned round at the noise. If the threshing machine was running it must have been pretty noisy anyway but the boy has obviously turned just when he shouldn't have.

Apart from a dark shape on the stack on the left which could be a dog, there is nobody else around.
Why was the boy being photographed in front of the machine?
Why has the photo been folded twice and put in a book?
Was he perhaps on holiday nearby?

My theory is that it had been decided that the photo wasn't good enough to be included in the family album so somone,needing a bookmark, picked it up and used it.