1. An image processing method comprising the steps of: separating first image data of an image into image data of objects and image data of background; obtaining feature amounts of objects from the image data of objects; determining front-back relations among the objects using sizes of the objects based on proximity of the objects with regard to a front side of the image; processing the image data of the objects in accordance with the front-back relations among the objects determined by the feature amounts; and combining the image data of the objects after the processing with the image data of the background to generate second image data, wherein the processing step and the combination step are carried out so that a sense of depth or stereoscopic effect of an image formed from the second image data is increased compared to a sense of depth or stereoscopic effect of an image formed from the first image data.