1. An image classification method, comprising the steps of: dividing an input image into blocks; obtaining a plurality of types of color statistic values of pixels in each block of the image; performing an evaluation of each block by calculating a weighted sum of the plurality of types of color statistic values of pixels in the block, in which the plurality of types of color statistic values are respectively weighted; obtaining image features based on the evaluations of the blocks of the image; and classifying the image based on the image features into pre-defined categories.