>>> """
===============
Watermark image
===============

Using a PNG file as a watermark.
"""
... 
... import numpy as np
... import matplotlib.cbook as cbook
... import matplotlib.image as image
... import matplotlib.pyplot as plt
... 
... 
... with cbook.get_sample_data('logo2.png') as file:
...     im = image.imread(file)
... 
... fig, ax = plt.subplots()
... 
... ax.plot(np.sin(10 * np.linspace(0, 1)), '-o', ms=20, alpha=0.7, mfc='orange')
... ax.grid()
... fig.figimage(im, 10, 10, zorder=3, alpha=.5)
... 
... plt.show()
... 
... #############################################################################
... #
... # .. admonition:: References
... #
... #    The use of the following functions, methods, classes and modules is shown
... #    in this example:
... #
... #    - `matplotlib.image`
... #    - `matplotlib.image.imread` / `matplotlib.pyplot.imread`
... #    - `matplotlib.figure.Figure.figimage`
...