sample PNGs for LargeTemplate [tiling] example do not open with Pillow 7.2

[dregula]

Thanks for this fascinating and useful code.
I was perplexed when attempting to run the LargeTemplate [tiling] example, always getting an out-of-range error.
imread was dropped from scipy.misc after v1.2, so I tried: forcing a scipy version < 1.2, using imageio.imread (as suggested in the SciPy documentation), and cv2.imread.
I finally realized that all of these attempts resulted in an all-zero numpy-array after opening resources/examples/tiling/big.png and small.png
I am an imaging novice, so I converted those sample images to a white background and the Large Template example went perfectly as expected (I think the sample PNGs have a transparent background, alpha?)
Not entirely sure what module is actually loading these PNG images, but I am using Pillow 7.2
Would it be possible to update the imreg_dft repository to include sample PNGs with a white background under resources/examples/tiling?
Thank you in advance!