A system LSI (10) serving as an image transmitter is a device for transmitting image data to a display device LCD (20) connected using a data signal line (32). The system LSI (10) is equipped with an output image memory (11) for storing image data to be transmitted, a subtraction processing unit (14) that reads the image data from the output image memory (11) and finds difference data between all of the adjacent pixels in the image data, and a data transmission unit (12) that successively outputs data signals, that represent the difference data corresponding to each of the pixels, in the form of binary numbers to the data signal line (32) according to the arrangement of the pixels. The transmitter is configured to output data signals for difference data whereby the number of times the signal changes is reduced more than when the image data are output to the data signal line (32).