I'm guessing that even though the 3rd datacenter is about 35km away from the other 2, and so the building isn't in the expected destruction zone of a 1MT warhead, the damage to the city's electricity/water/network infrastructure would take the 3rd datacenter offline as well - so while your cat pictures are probably still in existence on the no-longer-spinning-rust there, they'd be unaccessible for quite some time.