An image display system transforming LCD panels of mobile devices into being compatible with medical images display standard includes a host display panel, a slave mobile display device and a host computer. The host computer is coupled to the host display panel and the slave mobile display device for executing a process of sharing medical image, wherein the process of sharing medical image includes executing an image capture program to capture a color medical image, performing an image processing process to convert the color medical image into a grayscale medical image, converting the grayscale medical image into an image package, and connecting to the slave mobile display device to transmit the image package to the slave mobile display device.