1. An image-editing device comprising: display means for displaying images having a plurality of pixel value regions including an attention region; setting means for setting a graphic passing through the attention region and at least one region different from the attention region on an image; and control means for determining which of said regions contains ending-points of the set graphic, executing either extension or deletion on the attention region according to the result of the determination and the graphic, and causing the display means to display the region on which the extension or deletion is executed as a new attention region.