§ 256. Photographic reproduction of records. Any photograph, microphotograph or reproduction on film of any of the documents and records of a savings bank relating to the accounts of its depositors and the operation of its business, which such savings bank has caused to be made in the conduct of its business, shall be deemed to be the equivalent of the original thereof for all purposes, provided that the original of any such documents and records has been destroyed, that such photograph, microphotograph or reproduction on film shall be of durable material, and that the device used to reproduce such documents and records shall be one which accurately reproduces the original thereof in all details.