To partially process document images and to efficiently transmit and store them without damaging the information of structured image data.

This method is provided with a divided area determining step for inputting the structured image data composed of document image data and location data thereof and input data composed of area data showing plural areas inside the document image data and determining the area to divide in the document image data corresponding to prescribed division information, an image dividing step for dividing the document image data into a plurality of document image data corresponding to the area to divide. An image processing step for respectively partially processing the divided document image data, and a structured image updating step for updating the structured image data by respectively replacing the location data and the document image data before processing with data after image processing.