1. An image diagnosis apparatus comprising: an irradiator to emit radiation to a target object under at least two different conditions of the irradiator; a target object compression unit to compress the target object at at least two different compression intensities corresponding to the at least two different conditions of the irradiator; an image collector to collect a plurality of images with respect to the compressed target object while the target object is compressed at the at least two different compression intensities; and an image generator to generate a composite image with respect to the target object, based on the plurality of collected images.