Will it delete images of old deleted posts?

@bukharifaran No this plugin will not work for already deleted posts.

It will work only when installed on WordPress setup. it will clear image as soon as you delete the post.

• This reply was modified 5 years, 11 months ago by 1naveengiri.

Try this:
https://michaelpilsner.com/delete-images-media-gallery-wordpress-post-moved-trash/

This works for me:

add_action( ‘before_delete_post’, function( $id ) {
$attachments = get_attached_media( ”, $id );
foreach ($attachments as $attachment) {
wp_delete_attachment( $attachment->ID, ‘true’ );
}
} );

IMPORTANT: Keep in mind it will only be called when the posts are permanently deleted from the trash! If you want to change this behaviour, include the following line in your wp-config.php file:

define(‘EMPTY_TRASH_DAYS’, 0);