Image thumbnails not appearing in Media Library

Hi, I updated to the most recent version (2.5.2) of Smush Pro. After the upgrade, the image thumbnails are not appearing in the Media Library. I have a cloned site running with Smush Pro 2.4.5 and it's functioning properly. When I deactivate the 2.5.2 Smush Pro, the image thumbnails show up on upload. Thank you.