1. An image processing system comprising: a storage section which stores darkroom-condition-measurement data obtained by measuring a display region on which a plurality of calibration images are sequentially displayed under a darkroom condition, each of the plurality of calibration images having a different color, the display region being measured for each of the plurality of calibration images through a sensor; a supposed measurement data generating section which generates supposed measurement data based on viewing-environment-measurement data and the darkroom-condition-measurement data, the viewing-environment-measurement data being obtained by measuring the display region on which one of the plurality of calibration images is displayed under a viewing environment through the sensor; and a correcting section which corrects predetermined image correcting data by grasping a difference between the darkroom condition and the viewing environment based on the darkroom-condition-measurement data and the supposed measurement data, and also corrects image information used for image display based on the corrected image correcting data.