§ 239-a. Preservation of books and records. Every savings bank shall preserve all its records of final entry, including cards used under the card system and deposit tickets, for a period of at least six years from the date of making the same or from the date of the last entry thereon; provided, however, that preservation of photographic reproductions thereof or records in photographic form shall constitute compliance with the requirements of this section. Notwithstanding the foregoing, the superintendent of financial services may prescribe by regulation such period of time longer or shorter than six years during which all records kept by saving banks as fiduciary shall be preserved in original form.