PR Summary

Follow up to #23870. It seems I somehow missed a couple of warnings that are thrown when running make html-noplot. Perhaps my branch was not fully up-to-date.

/home/ruth/git_stuff/matplotlib/doc/tutorials/intermediate/constrainedlayout_guide.rst:: WARNING: image file not readable: _static/constrained_layout_1b.png
/home/ruth/git_stuff/matplotlib/doc/tutorials/intermediate/constrainedlayout_guide.rst:: WARNING: image file not readable: _static/constrained_layout_2b.png

My current change is very specific to the constrained layout tutorial, but it looks like the image handling in the constrained layout tutorial is very specific to issues encountered there: #22289 (comment), sphinx-gallery/sphinx-gallery#726.

PR Checklist

Tests and Styling

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (install flake8-docstrings and run flake8 --docstring-convention=all).

Documentation

• Documentation is sphinx and numpydoc compliant (the docs should build without error).
• New plotting related features are documented with examples.

Release Notes

• New features are marked with a .. versionadded:: directive in the docstring and documented in doc/users/next_whats_new/
• API changes are marked with a .. versionchanged:: directive in the docstring and documented in doc/api/next_api_changes/
• Release notes conform with instructions in next_whats_new/README.rst or next_api_changes/README.rst