1. An image processing method in which a reduced image is generated by removing some of a plurality of pixels of an original image, the image processing method comprising: reflecting a pixel value of a pixel to be removed into a pixel value of a pixel adjacent to the pixel to be removed, resulting in an update pixel value; removing the pixel to be removed; and generating the reduced image using the reflection result and the removal result; wherein the reflecting of the pixel value comprises updating the update pixel value to 1 when the value of the pixel to be removed and the value of the update pixel are different from each other and pixel value data is 1, and updating the update pixel value to 0 when the value of the pixel to be removed and the value of the update pixel are different from each other and the pixel value data is 0; and wherein the update pixel indicates a pixel that is adjacent to the pixel to be removed and is not to be removed, the pixel value data is a predetermined value used to update the update pixel, and the pixel value data may be toggled when the updating is performed by referring to the pixel value data and a direction in which the pixel value data is toggled is perpendicular to a direction in which the original image is reduced.