1. An image display method for displaying two or more images of an identical object to be compared, the method comprising: using an image display apparatus to perform the steps of: applying a non-linear warping operation to the two or more images so that the two or more images are displayed together in a row or a column with positions of a structural feature area of the identical object in the two or more images aligned horizontally or vertically, wherein the two or more images of the identical object to be compared include at least one of a plurality of original images and a subtraction image, which is derived by matching positions of two images selected out of said plurality of original: images and taking a differential between the selected two images.