""" Use a PNG file as a watermark """ import numpy as np import matplotlib import matplotlib.cbook as cbook import matplotlib.image as image import matplotlib.pyplot as plt datafile = cbook.get_sample_data('logo2.png', asfileobj=False) print 'loading', datafile im = image.imread(datafile) im[:,:,-1] = 0.5 # set the alpha channel fig = plt.figure() ax = fig.add_subplot(111) ax.plot(np.random.rand(20), '-o', ms=20, lw=2, alpha=0.7, mfc='orange') ax.grid() fig.figimage(im, 10, 10) plt.show()