I see hijacked pictures in the guitar world all the time, both from other e-bay ads and from dealer websites.
One way to answer your questions is to ask for a proof of life photo. Ask the seller to take a picture of the watch next to today's paper. Or a can of Coke. Something to prove that he has possession.
I once had a seller take a pic of a guitar in the bathroom. His son had the same bath toys as mine.
best
Allen