An image-forming device includes a casing, an accommodating section, a reading unit, a determining unit, and a printing unit. The casing defines an outer frame. The accommodating section is detachably mounted in the casing and configured to accommodate a stack of sheets, each sheet having a storage section capable of storing data. The reading unit reads data stored in the storage section. The determining unit determines, based on data read by the reading unit and additional data, whether to print an image corresponding to image data, the additional data being added to the image data. The printing unit prints the image on a sheet based on the image data when the determining unit allows printing to be performed.