The present invention provides an image display system which can simplify an operation of an operator for displaying images appropriate for diagnosis. An image display system according to the present invention includes a first obtaining unit configured to obtain first image data piece, a second obtaining unit configured to obtain a first meta-information piece regarding the first image data piece, a third obtaining unit configured to obtain a second image data piece, a fourth obtaining unit configured to obtain a second meta-information piece regarding the second image data piece, and a display control unit configured to determine a superimposition style corresponding to a combination of the first and second meta-information pieces based on the first and second meta-information pieces and display a superimposition image of the first and second image data pieces in the superimposition style on a display unit.