This is one way to protect the images from unregistred users :
Go to Config - User settings - Allow unlogged users (guest or anonymous) access and choose from:
No
Yes: thumbnail only
Yes: thumbnail and intermediate image
Yes: thumbnail, intermediate...
Go to Config - User settings - Allow unlogged users (guest or anonymous) access and choose from:
No
Yes: thumbnail only
Yes: thumbnail and intermediate image
Yes: thumbnail, intermediate...