An image forming device executes a plurality of applications, and includes a scan controlling unit configured to instruct an image reading unit to read image data, and store the image data in an image data storage unit according to a request from the application; a display data generating unit configured to generate a display data of the image data stored in the image data storage unit, and store the display data in a display image data storage unit according to the request from the application, the display image data storage unit being inaccessible from the application; a display controlling unit configured to display the display data in a display unit according to the request from the application; and a deleting unit configured to delete the display data from the display data storage unit in response to a termination notice of use of the display data from the application.