Since the algorithm can only detect the relative swirled amounts of a set of the same images, a solution could be to, rather than using a set of the same image,

Since the algorithm can only detect the relative swirled amounts of a set of the same images, a solution could be to, rather than using a set of the same image, use a set of different images swirled different amounts (or with some other transformation), and the user must select the unmodified image.