`oxipng -omax -Z` manages to reduce these images by 1.7 MB. This seems a worthwhile saving for anyone opening Introduction.md on GitHub (or elsewhere!).
Pull request: https://github.com/WebKit/WebKit/pull/16278
<rdar://problem/113571806>
Committed 270537@main (2c5a23bd4046): <https://commits.webkit.org/270537@main> Reviewed commits have been landed. Closing PR #16278 and removing active labels.