I am sorry to say that, but before giving a one-star review, you should make sure that you understand how WordPress works – and also, if you don’t understand something, have a question, or think there is an issue, the Support Thread forums are for that.
I downloaded the plugin had it analyze by WP installation and of the thousands of images there, it only found two not in use.
It means that only two of your Media entries are not used.
What it does it check the image grouping, not the various sizes, so if at least one version of the image is being used, then it considers all of them in use.
It’s not an image “grouping”. On WordPress, you have media entries. A media entry consists of many files: the original file + various thumbnails. Those thumbnails are generated based on your image sizes, which are set up by WordPress and generally, your theme (could be WooCommerce and more plugins).
So now, you wonder why those additional files are not being deleted; it’s because they are actually in use. They are part of the metadata. Even if you feel like they are not used, technically, they are, and they can be displayed by the specific theme or another plugin you have at anytime. If you delete them, they will be generated again in the future, automatically.
What you want to clean is actually the metadata; but for that, that means you agree to disagree with what your theme is doing, or your plugins are doing. If you really want to do that, here is how to disable certain image sizes: https://meowapps.com/wp-retina-2x-tutorial/. But that is not about cleaning, it’s about overriding your theme/plugins behavior.
Another thing now, about Media Cleaner, in its Pro version. There is a Filesystem Method which will detect all the files (those thumbnails) which are not registered in the metadata anymore. That happens if you switch plugins/themes a lot. That method will indeed clean the useless files.
But otherwise, files which are part of the metadata shouldn’t be removed.
I hope you’ll learn something by reading this, and consider reviewing your review based on this knowledge. That will also keep you from making mistakes with your WordPress install.
And remember, when you have an issue, ask the developers first. A lot of us are trying our best. In my case, I have been working on this plugin every day for the past 6 years.
