How do you change the lion lock screen

Good question!

I also would like to find that out.

It typically uses your Screen Saver definition in System Preferences > Desktop & Screen Saver > Screen Saver tab.

Or I'm misunderstanding the question...

Captfred

not the screensaver, and not the "Login WIndow".

When you wake up the computer, there is screen when input the password. That's the screen/background/wallpaper I want to change.

Go to Library/Desktop Pictures and copy your background image there. Rename the original bacground Andromeda Galaxy.jpg to e.g. Andromeda Galaxy original.jpg and your bacground image to Andromeda Galaxy.jpg. That should do the trick.

awesome! I like this trick. 🙂