Does what it says

It does what it says. In Settings > Media you can see all the registered image sizes set by wordpress and your theme / plugins. The reason I gave it 3 stars is because it works but I tested it on a testing environment with WP_DEBUG == true and it broke the site. The plugin must be using the ‘init’ or ‘after_the_setup’ hook which can break things in debug mode die to the fact it tries to alter the ‘header’ (php server request header not header.php).

Anyways, it works fine on a normal production environment