1. An image display panel, comprising a histogram generator, receiving an original image, counting the pixels of different gray levels to generate a histogram distribution of the original image, and comparing the pixel counts at every gray level with a first threshold count to identify the peaks of the histogram distribution; a tone slope generator, generating a tone slope based on the histogram distribution and the peaks of the histogram distribution; and an image transformer, transforming the original image into a modified image based on the tone slope.