1. A method for processing each of a plurality of chest X-ray images photographed by an X-ray imaging apparatus, said method comprising: analyzing at least one of size characteristics of pulmonary hila of lung images and a characteristic of intensity of each pulmonary-hilum image of lung images in the plurality of chest X-ray images; applying a point to each characteristic in the chest X-ray images based on a result of the analysis of the characteristics of the pulmonary hila; sorting the chest X-ray images into a normal group and an un-normal group based on a result of the analysis of the characteristics of the pulmonary hila, wherein sorting the chest X-ray images includes ranking the chest X-ray images based on the total points in each chest X-ray image; and displaying a result of the sorting.