a reading unit constructed to read an image;

a generating unit constructed to generate line image data representing at least part of the image;

a line buffering unit constructed to buffer at least a portion of the line image data;

a header buffer unit constructed to buffer a character code set;

an expansion unit constructed to expand the character code set into an expanded character code set;

a conversion unit constructed to convert the expanded character code set to a converted character code set equivalent to a number of lines of a minimum coded unit for JPEG compression processing, the converted character code set including transmission information for at least one of a page header and a page footer;

an extracting unit constructed to sequentially extract, from the line buffer unit, an amount of the line image data equivalent to the number of lines of the minimum coded unit for JPEG compression processing;

an exchanging unit constructed to exchange the number of lines of the minimum coded unit for JPEG compression from the line image data extracted by said extracting unit with the transmission information when the lines of the extracted image data correspond to at least one of a header portion in the image and a footer portion in the image;

a compressing unit constructed to sequentially execute JPEG compression processing for each minimum coded unit of the extracted image data including the transmission information;

a storing unit constructed to store compressed data output by said compressing unit in a memory; and

a transmitting unit constructed to transmit a JPEG image data based on the compressed data stored in the memory.