Image classification methods and systems are provided. First, an image is obtained using a computer. The image is then processed using the computer to obtain image information. The image information includes one or any combination of an average color difference between at least one average channel value of pixels in at least one boundary region of the image and a predefined standard value, a gradient variation magnitude difference between at least two regions of the image, and a percentage of the edges of the image to the image. The image is classified using the computer according to the image information.