1. A method for comparing images, the method comprising: computing, using a processor, a first image feature vector based on a plurality of characteristics of a first image, the first image comprising a scanned image of a physical periodical or a physical book; and comparing the first image feature vector to a second image feature vector stored in a database, wherein the first image feature vector comprises a first aspect ratio representing a first ratio of a first pixel height to a first pixel width of the first image, and the second image feature vector comprises a second aspect ratio representing a second ratio of a second pixel height to a second pixel width of a reference image.