To provide an image display processing method for quickly displaying an image on an image display apparatus and preventing the rotation of the image possibly caused when the display of thumbnail pictures is switched into the display of a main picture.

A flowchart indicating an example of image display output processing includes: a step S110 of acquiring longitudinal and lateral sizes of the main picture, longitudinal and lateral sizes of the thumbnail pictures, and the rotating direction of the thumbnail pictures from a header of an image file, and discriminating whether the main picture and the thumbnail pictures are longitudinally long pictures or laterally long pictures; and steps S150, S160 of rotating the thumbnail pictures by 90 degrees and displaying the resulting thumbnail pictures on a liquid crystal display apparatus when the size of the main picture is a prescribed size or over and thereafter displaying the main picture in place of the thumbnail pictures on the liquid crystal display apparatus. Thus, the pictures can quickly be displayed and the rotation of the pictures at display switching can be prevented.