When image data which is decoded after being irreversibly compressed is to be displayed, this invention makes it possible to display a histogram close to the exposure conditions perceived by the human sense during photography. This invention includes a histogram acquisition unit which acquires histogram information from input image data, an encoding unit which generates encoded image data by encoding the input image data or by encoding image data obtained by performing predetermined processing on the input image data, and a recording unit which records the encoded image data and histogram information.