An image display system includes: a storage section that stores plural image data sets and layout information indicating layout of one or plural sub images forming, as a whole, a background image behind a main image; a main image select section that selects one image data as a main image data set expressing a main image, from the plural image data sets; a characteristic specify section that specifies a characteristic of the main image data set selected by the main image select section; a sub image extract section that extracts, as one or plural image data sets each expressing a sub image, one or plural image data sets each having a characteristic making a relationship with the characteristic specified by the characteristic specify section, among the plural image data sets stored in the storage section except the main image data set, whereby the relationship satisfies a predetermined condition; and an image display section that displays the main image selected by the main image select section and the one or plural sub images extracted by the sub image extract section, in accordance with the layout information stored in the storage section.