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 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; and a thumbnail display controller for producing thumbnails of said stored images and displaying the thumbnails in an array on said display device, said thumbnail display controller controlling displaying the thumbnails in variable sizes according to the importance degrees of the respective keywords set through said importance degree setting section.