Given the importance of regional centers for medical image sharing and cooperation is important for resource balancing, healthcare service enhancement and medical expense reduction, building such regional medical image sharing and cooperation centers faces huge challenges. In this paper we analyze the advantages and weakness of two storage architectures, and designed a hybrid storage architecture combining FC SAN and Hadoop HDFS. A HDFS suitable medical image file format, called S-DICOM, and a set of S-DICOM operating middleware, SDFO (S-DICOM File Operator), was developed. The results of performance testing indicated that this hybrid storage architecture is suitable for storing and managing large volume of medical images.