def METHOD_NAME(img_ref, img_warp, fig_name):
    fig, axarr = plt.subplots(ncols=2, figsize=(12, 5))
    axarr[0].set_title('warped image & reference contour')
    axarr[0].imshow(img_warp)
    axarr[0].contour(img_ref, colors='r')
    ssd = np.sum((img_warp - img_ref) ** 2)
    axarr[1].set_title('difference, SSD=%.02f' % ssd)
    im = axarr[1].imshow(img_warp - img_ref)
    plt.colorbar(im)
    fig.tight_layout()
    fig.savefig(fig_name + '.png')