PURPOSE: To obtain an image having the desirable picture quality without expanding the compressed image data over an entire screen for hierarchy when the compressed image data coded progressibly are expanded.

CONSTITUTION: The original image data are subjected to the DCT conversion and the conversion coefficient is divided into quadripartite bands B1-B4. Then these bands B1-B4 are turned into the Huffman codes. Thus the compressed image data are obtained. When these compressed data are expanded, the compressed image data are first expanded on the entire screen for the first band B1. When the areas are designated for the extraction of the compressed image data in regard of the second and subsequent bands. Thus the compressed image data of the designated areas only are extracted and expanded. Then the picture quality is improved in the image data extracting areas.