The method is for recognizing and indexing a digital image. The digital image is converted to a gray-scaled image. A first pixel value of a first pixel, a second pixel value of a second pixel and a third value of a third pixel are identified. A first difference between the first pixel value and the second pixel value and a second difference between the second pixel value and the third pixel value are determined. The first difference is compared with the second difference. A number of occurrences of each pixel difference are determined. A threshold difference is identified that corresponds to a dynamic threshold value of the number of occurrences. Each difference that is greater than the threshold difference is determined to be an edge pixel.