How to export plots from matplotlib with transparent background?

Use the matplotlib savefig function with the keyword argument transparent=True to save the image as a png file.

In [28]: import numpy as np

In [29]: from matplotlib.pyplot import plot, savefig

In [30]: x = np.linspace(0,6,31)

In [31]: y = np.exp(-0.5*x) * np.sin(x)

In [32]: plot(x, y, 'bo-')
Out[32]: [<matplotlib.lines.Line2D at 0x3f29750>]            

In [33]: savefig('demo.png', transparent=True)

Result:

Of course, that plot doesn't demonstrate the transparency. Here's a screenshot of the PNG file displayed using the ImageMagick display command. The checkerboard pattern is the background that is visible through the transparent parts of the PNG file.

As a reminder, the plt.savefig() should be written before the plt.show(), otherwise, a transparent image will be created (without the actual plot).

For high-quality images:

plt.savefig('filename.png', format='png', dpi='600', transparent=True)
plt.show()