1. A method of generating an image, the method comprising: generating a plurality of images by adjusting an exposure amount and a resolution of the plurality of images; making the resolutions of the generated plurality of images identical; and synthesizing the plurality of images having the identical resolutions, wherein the generating of the plurality of images comprises: generating a first image, and generating a second image with a lower resolution than that of the first image, and, wherein the synthesizing of the images comprises: decreasing the resolution of the first image to that of the second image, and synthesizing the first image having the decreased resolution and the second image.