An image forming device is provided with an external storage, a printing unit, a storage controlling unit configured to store the image data in the external storage or an internal storage. The storage controlling device stores the image data developed from the print data retrieved from the print data stored in the external in the external storage, while stores the image data developed from the print data transmitted from the external device in the internal storage. At least file names of image data stored in the external storage on the displaying unit are displayed for selection when the external storage is connected to the image forming device, and file names of image data stored in the internal storage are displayed when the external storage is not connected to the image forming device. A reprinting unit performs a reprinting operation based on the selected image data.