The dog is probably one of the bomb-sniffing dogs that work at a CIA building or campus. Any information about the security for CIA locations, I'm assuming, is

The dog is probably one of the bomb-sniffing dogs that work at a CIA building or campus. Any information about the security for CIA locations, I'm assuming, is going to be very well protected information so this is going to include any pictures of the security forces. The picture is just a dog chewing on a stick but the dog is part of the security force and therefore the picture becomes classified. It probably didn't need to be classified. We aren't using some sort of super advanced, secret machine to detect bombs, it's a regular yellow lab. It was probably included in a bunch of pictures that included information regarding the tactics or tools available to the security forces or pictures of secured areas (that aren't generic grassy areas) so the whole group was classified.