PR Summary

Closes #15517.

This failed the new test on master, and passes now.

The test from #15517 yields:

from pylab import *
plt.rcdefaults()
fig, axs = plt.subplots(1, 2)
axs[0].imshow(np.random.rand(10, 10))  # now defaults to interpolation="antialiased"
axs[1].imshow(np.random.rand(1000, 1000))
axs[1].set(xlim=(-.5, 9.5), ylim=(-.5, 9.5))
plt.show()

and it works under interactive use as far as I can see.

PR Checklist

• Has Pytest style unit tests
• Code is Flake 8 compliant
• New features are documented, with examples if plot related
• Documentation is sphinx and numpydoc compliant
• Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
• Documented in doc/api/api_changes.rst if API changed in a backward-incompatible way