Question

In numpy/scipy I have an image stored in an array. I can display it, I want to save it using savefig without any borders, axes, labels, titles,… Just pure image, nothing else.

I want to avoid packages like PyPNG or scipy.misc.imsave, they are sometimes problematic (they do not always install well, only basic savefig() for me

Answer 1

EDIT

Changed aspect='normal to aspect='auto' since that changed in more recent versions of matplotlib (thanks to @Luke19).

---

Assuming :

import matplotlib.pyplot as plt

To make a figure without the frame :

fig = plt.figure(frameon=False)
fig.set_size_inches(w,h)

To make the content fill the whole figure

ax = plt.Axes(fig, [0., 0., 1., 1.])
ax.set_axis_off()
fig.add_axes(ax)

Then draw your image on it :

ax.imshow(your_image, aspect='auto')
fig.savefig(fname, dpi)

The aspect parameter changes the pixel size to make sure they fill the figure size specified in fig.set_size_inches(…). To get a feel of how to play with this sort of things, read through matplotlib’s documentation, particularly on the subject of Axes, Axis and Artist.