[Smush Pro] Clarification on smush pro image processing.

In the images attached I show 5 images for jellfish-underwater-PWQTR9X-tny-3.jpg actualy in the upload directory. In the media library a reset and re smush creates 12 images. In this site there are 12 media image size settings. It was my understanding that smush pro only smushed existing images but I am seeing that smush will generate all registered images regardless of actuall images in the upload. Is this a bug or is this by design? If bug fix it if by design fix it. smush should only process actual images in the upload directory.