To achieve a transfer of image data of large capacity from a host system side to a display side and a transfer of a far small quantity of data from the display side to the host system side with the maximum efficiency.An image display method which transfers image data between a host system side executing an application and a display side displaying an image, which includes the steps of: managing image data by the host system side, which belongs to a window in accordance with a sub-area obtained by dividing a display area of the display side, the window that is a region making sense in an image space of which the application is conscious; transferring the image data as a unit of a packet to the display side via the digital I/F; developing the image data transferred in a panel memory of the display side; grasping conditions concerning a transfer error in a unit of a window; and grasping the conditions of the transfer error through a signal line by the host system side.