1. A method of generating a saliency image, the method comprising: converting an input image into an input image of the first size and an input image of the second size; applying a saliency extraction scheme to the input image of the first size to generate a first saliency image; converting the first saliency image to the second size; extracting an area that satisfies a first condition from the converted first saliency image; determining an area of the input image of the second size that corresponds to the extracted area; and generating a second saliency image by multiplying an image generated by applying the saliency extraction scheme to the determined area, and the converted first saliency image.