There is provided a network system, which comprises an image reading device and an image display device connected to the image reading device via a network. In the network system, the image reading device comprises a reading unit to read an image from an original and to generate image data, a communication unit, a communication controller to activate the reading unit and to transmit the image data to the image display device in response to receipt of an image transfer instruction. The image display device comprises a communication unit, a instruction input unit through which the image transfer instruction is inputted, a communication controller to transmit the image transfer instruction inputted through the instruction input unit to the image reading device, and a display control unit to display an image corresponding to the image data in response to receipt of the image data.