Hotlink protection
Hotlink protection prevents other sites from stealing your bandwidth and using images hosted on your site for display on sites that do not belong to you. All images residing on your site are automatically protected if Hotlink protection is enabled (file extensions: .gif, .ico, .jpg, .jpeg, .png).
Anyone that attempts to reference an image on your site with Hotlink protection will only see a broken image instead. You can bypass Hotlink protection by creating the folder hotlink-ok anywhere on your site and copying only those images that are allowed to be hotlinked into that folder.