In reply to Robert Trevellyan.

@robert
If you have so many unused images in your media library to have an actual performance impact you should ask yourself how did you get there.

I would assume that most people do not upload images "just because".

@junas
As I said I don't think the plugin is useless, just that you emphesize the wrong functionality.

The internet is interconnected and just because a image is not used on the site do not mean it is not used on other sites. Maybe you host it on one of your sites while using it on another. Maybe you use it in some public API integration (opengraph comes to mind, but also newsletters authored outside of the site are good candidates), so does anyone can be 100% sure that deleting an image has no impact? This is where the plugin needs to show its ROI as the effort in making sure an attachment can actually be deleted might not be trivial at all.

The original problem here is that all attachments are public once they are uploaded and therefor you do not have an "not published" state for attachments that you could have used as signal that it is truly not used.