eleventyImageTransformPlugin with extensionless files

[btrem]

I output two html file patterns:

1. index.html for directory indexes, e.g., _site/index.html for the home page, or _site/2025/index.html for posts from 2025.
2. extensionless html files for individual posts, e.g., _site/2025/my-post. (I serve these as text/html with ForceType 'text/html; charset=utf-8' inside an Apache configuration FilesMatch block.)

eleventyImageTransformPlugin by default only transforms images for the first category, any index.html files. I can change it to include other extensions. Can I modify it to include extensionless files?