You can't view anyone's pictures at ALL if you're not logged in, even if you have the URL that's directly tied to one members Photo Gallery. You also can't view the main Photo Gallery page, even with the URL. You'll just get a blank page.

This is what you get when you have the DIRECT URL to the Photo Gallery (main):

http://i2.photobucket.com/albums/y40...ermission2.jpg

This is what you get when you have the direct link URL to a specific members (personal) Photo Gallery.

http://i2.photobucket.com/albums/y40...permission.jpg

...........

So no, an unregistered or a member who is not signed in cannot view any of the photos. I actually logged out to test things out just to make sure too.