When we importing new image file and removing old files we have old image in our file system, but link to that image is removing from DB. In Media attribute backend model we have [removing link to file from DB](https://github.com/magento/magento2/blob/master/app/code/Magento/Catalog/Model/Product/Attribute/Backend/Media.php#L350), but haven't removing it from file system. When we have 100k+ products and make product import frequently, disk space is really fast ends. This issue is also reproducing in Magento 1.