1. An image processing device, comprising: a region extraction unit for separating and extracting a character region, a graphic region and a photograph region from image data; a region compression unit for performing a compression process for each of the region data extracted by said region extraction unit; a region synthesis unit for synthesizing the region data compressed by said region compression unit; and a compression method selection unit for selecting a compression method of the compression process to be performed for each of the region data extracted by said region extraction unit from among a plurality of compression methods designated individually for types of the region data; said region compression unit performing the compression process for each of the region data using the compression method selected for the region data by said compression method selection unit.