How to delete or autodelete unused images in a Drupal site? Every time I remove or replace an image in my Drupal 7 site (via image-field or CKeditor) it remains stored in the site's folder (x3 times at least for every style). Almost always it takes me about 3 MB of storage and creates a mess in the "styles" folder.

Is there a way (or module) to issue a command to remove all image files which are not being used (anymore) at my site?
The following drush command:

drush image-flush


may be used to remove all the image style copies generated as image styles via image-field or CKeditor. This is completely safe, as it will not touch the originals.

Those still in use will be regenerated when needed.  Those no longer used will not not be regenerated.

As noted in a comment by cptstarling:


  If you don't have access to drush, you may consider the Image style flush module.