Hi,
I read multi time your article, but still not really understand.
The plugin can do a lot of things; but it depends also on what you want to do. What’s your goal? ??
does your plugin make the new images upload and make them only with 3 version of images?
I am not sure I understand. WordPress generates the thumbnails for all the registered sizes. With my plugin, you can unregister some sizes. And to clean everything, you can regenerate the thumbnails with it, which will clean the related metadata.
As show in my image of the theme have around 20 different size of images, when using your plugin can save a lot of space on the hosting, does correct?
Yes, but you need to guess which images are useless. In your case, I would try to get rid of all the “fusion” sizes, the W1, W2, and the “medium large”.