Brilliant photo of an odd situation. Why was the leopard reacting that way? Food dangled behind the child, or was the child bait for the leopard? Haha.
I may be generalizing but I think this may be just leopard behaviour in general (I've never seen any other big cat in captivity behave this way so consistently). I worked in a zoo where a couple of leopards were kept and these cats frequently displayed very predatory behaviour / intent consisting of stalking and charges towards visitors.
It seemed that this was mainly / mostly directed towards children but I also remember once seeing this same predatory behaviour invoked by disabled people who were passing by the enclosures too.