A quick and accurate algorithm for content-based image retrieval (CBIR) is proposed in this paper. The retrieval of the similar images using proposed algorithm from the database is based on the statistical texture features. The basic idea is to convert the RGB color image into grayscale image to reduce the computation speed and increase efficiency. The grayscale image is divided into blocks of different sizes. The statistical texture features are extracted by using the probability distribution of intensity levels in all blocks. In the experiment, the efficiency of feature extraction and accuracy of the image retrieval are measured for different block size methods using the proposed algorithm. The Corel database was used for testing. As a result the proposed CBIR algorithm provided higher performance in terms of efficiency and accuracy. © 2011 IEEE.