A method of operating an image sensor, the image sensor including a pixel array of a plurality of red pixels, a plurality of green pixels, a plurality of blue pixels, and a plurality of white pixels, includes selecting a first green pixel and a second green pixel arranged on a first axis parallel to a first diagonal direction, selecting a third green pixel and a fourth green pixel arranged on a second axis parallel to a second diagonal direction, generating a first green binning pixel by performing a first diagonal binning operation on the first green pixel and the second green pixel, generating a second green binning pixel by performing a second diagonal binning operation on the third green pixel and the fourth green pixel, and generating image data corresponding to the first green binning pixel and the second green binning pixel.