Change Snow Leopard Login Wallpaper w/ Terminal

Question

I know this is possible as I did it once before.

How do you set the login background wallpaper to something else using terminal?

Answer 1

The login screen background image is located at /System/Library/CoreServices/DefaultDesktop.jpg — you can simply sudo cp another jpeg image to replace it (though I'd recommend backing it up first!).

Answer 2

You can do it using AppleScript:

tell application "Finder"
     set desktop picture to POSIX file "/path/to/file.jpg"
end tell

It should be fairly easy to package this in an Automator script.

Alternatively, you can use defaults:

defaults write com.apple.desktop Background '{default = {ImageFilePath = "/Library/Desktop Pictures/Black & White/Lightning.jpg"; };}'

I haven't tested this myself, so you may have to run killall Dock before this takes effect.

Edit: more information on this and launchd