imghdr is deprecated and slated for removal in Python 3.13

[labrys]

The Python standard library will be removing imghdr in Python 3.13. Per PEP-594 suggested replacements are filetype, puremagic, and python-magic.

[sampsyo]

Yes indeed—thanks for opening the issue. We should switch sooner rather than later.

(It's too bad about these deprecations, to be honest! I know they were rarely used, but they did their job quietly and well…)