The caption says: "Dr Vincent Drost recording the #pasmillionth object" on the PAS database.
The photo is as much of a sham as the claim that a million objects have been reported voluntarily. The desk is empty. Or perhaps the "millionth object" is actually invisible, only Dr Drost can see it? What you cannot see is the bin where, in true PAS fashion, he puts requests for further information from members of the public, see: PACHI Monday, 15 September 2014, 'Dr Vincent Drost, the Invisible man of the PAS (UPDATE)'.