New to MacBook Pro. Love the images in the Desktop Library and have been trying to add to them by finding pics on Google images. Sometimes when I add the pic it asks for my password for authentication, but sometimes it gives me a message saying that if I add the picture no one will be able to see it. I can't seem to make sense about why or why not this happens. And it happens a lot (my guess is has to do with some setting the owner set on the photo?). Any help appreciated. Thanks.