nice idea but also regenerates old thumbnails ...

[swedishboy]

It seems to look into the attachment-metadata and regenereate old (often obsolete sizes).
If that data hasn't been cleaned properly it can end up generating several extra image sizes that might not even be used by the current theme.

I think you should regenerate only the image sizes from get_intermediate_image_sizes, right? :)
https://codex.wordpress.org/Function_Reference/get_intermediate_image_sizes

The current behaviour might be useful, but should be an opt-in or alternate plugin (if you don't want to make a prefs screen for this one).

I'm working on cleaning out old image-sizes on a project i'm working with. The upload folder on this project had more than 30.000+ files (yep, it wasn't sorted into year/month either ...) so it was in desperate need of cleaning.

However what I'm looking for now is something to help me clean the attachment-metadata sizes. And this plugin did the opposite. Regenerating old thumbnail sizes I want to get rid of. :)