1. A method of generating a synthesized image by combining content of a first image with content of a second image, the first and second images being acquired by a portable terminal, comprising: displaying the first and second images; setting first and second portions of the second image as first and second regions of interest; in response to a first drag input from the first image to the first region of interest, displaying a first synthesized image by incorporating the first image in the first region of interest; and in response to a second drag input from the first region of interest to the second region of interest, displaying a second synthesized image by incorporating the first image in the second region of interest, wherein the first or second region of interest is defined by corner characteristic points which are automatically recognized in the second image, the corner characteristic points correspond to corners of an object in the second image, the first or second region of interest corresponds to a surface of the object defined by the corners of the object, and each of the corner characteristic points is movable according to a first user input, and wherein, when the surface of the object changes, the corner characteristic points are automatically moved according to the changed surface of the object.