PR summary

Goal

This pull request is made to address issue #29183. It closes #29183.

Implementation

This pull request added an if branch within the function imsave() in the path lib/matplotlib/image.py. It is added to handle the case addressed in issue #29183 where input arr is a vanilla python list.

Testing

One test case is added to lib/matplotlib/tests/test_image.py so there is a round trip from imread() to imsave(). Test input is designed to be a vanilla python list so that the newly added branch is covered in test suite.

PR checklist

• "closes #0000" is in the body of the PR description to link the related issue
• new and changed code is tested
• Plotting related features are demonstrated in an example
• New Features and API Changes are noted with a directive and release note
• Documentation complies with general and docstring guidelines