In this paper

a new image feature retrieval method is proposed for large number of JPEG format medical images.The retrieved result

including both space domain and frequency domain information

expresses image feature perfectly and makes content based query more accuracy. The retrieving can be done just afterHuffman decoding but needn’t restore the compressed image data to its original state

thus the time consumed by the algorithml is greatly decreased. The method that the query can be done from“rough”to“fine”according to JPEGmulti-resolution analysis is also presented.