1. An image signature creating method comprising: creating a map by partitioning a still image using rings defined by concentric circles radially spaced apart from each other by a predetermined interval and radial lines circumferentially spaced apart from each other by a predetermined angle, the center of the still image being that of the concentric circles; creating an image signature from the created map on the basis of a distribution of pixels in regions defined by the rings and the radial lines, wherein creating the image signature comprises: firstly calculating average distributions of pixels for the rings; secondly calculating a primary difference distribution of the calculated average distributions; thirdly calculating a secondary difference distribution using the primary difference distribution; and fourthly calculating angular difference distributions for the rings; converting the firstly to fourthly calculated distributions into bit strings; and creating the image signature by primarily integrating the bit strings.