Your code does three imshow() using the same implicit current axes. The second imshow() erases the first one; the third imshow() erases the second one. After the third imshow() you figure() and so create a new implicit current axes for the transformed image to be displayed in, so that one does not erase the previous one.
You should either be using figure() to show each image in its own figure, or you should be using subplot() to put them in different axes on the same figure, or you should be taking steps to display them all in a single axes, similar to the imshowpair() that is commented out.
