Hello, x1code!
The plugin can be used with all caching plugins. It doesn’t require any special integration. It also doesn’t run on the frontend. (all tasks are performed in the admin dashboard, which should never be cached)
If you have any orphan thumbnails or WEBP/AVIF images left on your server, it’s usually because the plugin or script that you use to generate them isn’t properly integrated with WordPress. Autoremove Attachments doesn’t delete any files directly. It only tells WordPress what files to delete. The actual removal is done by WordPress. And if WordPress is not aware of all your thumbnails or custom image formats, it will not remove them.
I don’t know what tool you use to generate your WEBP files, but you should probably switch to something else. It doesn’t matter if you use Autoremove Attachments or not – if WordPress doesn’t track your WEBP images, they will always become orphan files when you remove images from your media library.
I personally use and recommend WebP Express, which does things the WordPress way. It also provides granular control in terms of quality, delivery, and conversion method. It’s even compatible with thumbnail regeneration, either via the Regenerate Thumbnails plugin or WP-CLI.
Other good alternatives are ShortPixel and Imagify, but these are paid SaaS services with less control over the end result. (but they integrate well with WordPress and should work without any issues)
Regardless of which solution you choose, to prevent conflicts or unexpected results, make sure you first remove your old WEBP images from the server.