Patent attributes
This invention has as its object to allow information recording by maximally utilizing the size of a storage medium while maintaining compatibility to an electronic device which can handle only a storage medium initialized by the first file system to some extent. To this end, on a storage medium, two storage areas, i.e., a partition A initialized by the FAT16 file system to be accessed by a normal digital still camera, and a partition B initialized by the FAT32 file system that allows a still larger address space, are assured. A main image sensed by a camera unit is stored in the partition B, and a thumbnail image as its derivative information is stored in the partition A. Even when this memory card is attached to the conventional digital still camera, the thumbnail image can be browsed. Also, information indicating correspondence between the main image and corresponding thumbnail image is stored in the partition B as management information. As a result, even when a thumbnail image is detected by the conventional digital still camera, whether the main image is to be deleted or the deleted thumbnail image is to be restored can be selected based on the correspondence with the main image.