1. An image editing method comprising: a step of acquiring identification information on each of a plurality of operation instruction units for instructing editing of an image, a step of automatically selecting one or more images for editing from a group of images to classify the one or more images into a group of usable images based on the identification information, a step of determining a right to edit reaching contents of processing which each operation instruction unit is authorized to perform against each image in the group of usable images, and a step of performing editing processing on an image to be edited in the group of usable images based upon the determined right to edit according to an editing instruction supplied from each operation instruction unit, wherein determination of the right to edit is performed by storing time spent for editing the image for each operator and granting the operators the right to edit based on the stored time for each operator.