By default, each new sandbox uses the “uploads” folder of the main site.
It means the folder is shared and any change applied by the user (addition or removal of an image from the WordPress “media Library”) will directly affect the main installation and all the generated sandboxes.
PLEASE NOTE: the images added by the user will be automatically removed when the sandbox expires.
The plugin behaviour is different if you choose to enable the “Clone Uploads Directory” option.
In this case, the “uploads” folder with all the main site media will be cloned when the user creates the sandbox. Unlike previously stated, each change applied to the WordPress “Media Library” will have effects only and exclusively on the cloned folder.
The folder will be automatically deleted when the sandbox expires.