If this box is unchecked, users will not be able to see the uploaded files attached to a thing of this type. For example, let's say you set up a workflow where users can create an 'Apartment,' and that apartment has pictures. Set up the picture uploader in a way that links the picture to the actual apartment in the database. Then, if you uncheck this box and if the condition is 'This apartment's creator isn't current user,' other users will not be able to see that picture, even if an image displays it or if a user has a link to the image file.