1. An image display medium for displaying an image having a first region including a first composite image and a second region including a second composite image, the first composite image comprising: a first display image including at least one of a first halftone dot image and a first line image having a first linearity, the first halftone dot image and the first line image having such densities as are not reproduced by copying; a first latent image incorporated into the first display image including at least one of a second halftone dot image and a second line image having a second linearity, the second halftone dot image and the second line image having such densities as are not reproduced by copying, wherein the first linearity produces a moiré pattern different from a moiré pattern produced by the second linearity when the first display image and the first latent image are enlarged by a first common optical system; and the second composite image comprising: a second display image including at least one of a third halftone dot image and a third line image having a third linearity, the third halftone dot image and the third line image having such densities as are reproduced by copying; and a second latent image including at least one of a fourth halftone dot image and a fourth line image having a fourth linearity, the fourth halftone dot image and the fourth line image having such densities as are reproduced by copying, wherein the third linearity produces a moiré pattern different from a moiré pattern produced by the fourth linearity when the second display image and the second latent image are enlarged by a second common optical system.