Keep in mind, though, the purpose of the various folders. It's your computer, so you can decide what folders you want and what you want in them. The samples that Microsoft supplies are intended to get people started, so they don't get a new computer and have a blank piece of paper. The public folder is community space where everyone can share access to the same file. The public folder contains files intended to be shared by other users of your computer (physically using your computer or via a network). Your folder, of course, is your own files. Each of the folders is on the computer for a reason. You have access to your own folder and the public folder, so both of these will appear in the library. That includes not only you, but 'default user', 'public', etc. Each user account will get a My Pictures folder pre-populated with the same sample pictures. Some common folders come pre-populated with samples from Microsoft. A library is a tool for letting you view all of the similar things that may be in different locations on your computer that you have access to.
