It is a series of photographs taken of the property as defined by the lease or the client, usually internal and external views of the property and put into a schedule to attach to the lease.
A lease with the repair limited by a Photographic Schedule of Condition will record the condition of the property and is attached to the lease prior to completion/signing the lease.
This can assist either a landlord with a dilapidations claim at the end of a lease if your property has been returned in a poorer state than documented in the schedule, or a tenant who can provide proof that the property was in the same if not better condition than when they took it on if they are faced with an unexpected claim.