1. An image display apparatus, comprising: a display device for displaying images based on image data, said image data being stored for each image in an association with at least a keyword relating to said each image; an importance degree setting controller for producing and displaying an importance degree setting section on said display device, to permit setting each keyword associated with said stored image data at an appropriate importance degree; a thumbnail display controller for producing thumbnails of stored images and displaying the thumbnails in an order of a time and a date when said stored images are captured on said display device, said thumbnail display controller controlling displaying the thumbnails in variable sizes according to the importance degrees of respective keywords set through said importance degree setting section, and wherein, before sizes of the thumbnails are changed to said variable sizes according to the importance degrees of respective keywords, the thumbnails are displayed in a same size on said display device in the order of the time and the date when said stored images are captured.