1. A method of editing a combined image comprising a plurality of object images, the method comprising: determining coordinates of vertexes of an outline rectangle which forms outlines of an object image within the combined image, and displaying the outline rectangle according to the determined coordinates of vertexes; when a predetermined first operation is performed on an object image selected from among the object images located within the outline rectangle by performing a drag operation on the selected object from an internal portion of the outline rectangle to an outside of the outline rectangle, segmenting the selected object image and another object image located within the outline rectangle; when a predetermined second operation is performed on an object image within the outline rectangle selected from among the object images by performing the drag operation on the selected object image into another outline rectangle other than the outline rectangle, combining the selected object image with another object image located within the another outline rectangle; and renewing displaying of the outline rectangle according the segmenting or combining, wherein the determining the coordinates of the vertexes includes scaling the combined image with a predetermined resolution prior to converting the scaled combined image into a binary image, and calculating the coordinates of the vertexes using groups determined based on classifying areas of the binary image according to a predetermined category.