Change your login screen photo
When you log in or switch users, you will see a list of users with their login photos. You can change your photo to a stock image or an image of your own. You can even take a new login photo with your webcam.
Click your name in the menu bar and select User Accounts.
Click the picture next to your name. A drop-down gallery will be shown with some stock login photos. If you like one of them, click it to use it for yourself.
If you'd rather use a picture you already have on your computer, click Browse for more pictures.