If you wanna check the image sizes and content, go to 'Backup, Archive and Restore' interface on Java Console > Select client and policy type and then you will have the option (there are two buttons on the middle right side) to select images based on calendar (who opens a calendar) and another and other one where list all images found. In this second button (who opens the list) you will have the backup type and image size (as well as other informations like date for example). Selecting from this screen just a differential one, you will be able to see witch files have been copied from this stream.