Bored of the staid, old login background that greets you every time you log into your Mac? Here’s how to customize the wallpaper image to anything you want with just a couple of quick steps.
We’ll start off by showing you how to manually change the background image, and then how to use a simple application to change the image.
Changing the Background Manually
Open a Finder window and hit Command-Shift-G. Enter “/System/Library/CoreServices” in the text box that shows up and click “Go”:
That will take you to the CoreServices folder. Like its name implies, this folder contains important system files, including the login background image, among other things. The CoreServices folder will look like this:
Locate the image labeled “DefaultDesktop.jpg” and drag it to the trash. Don’t worry, you can always drag it back again, just as long as it’s out of the way.
If you have your replacement background image, rename it to “DefaultDesktop.jpg”. Yes, your image has to be a JPEG. If it isn’t, you can likely convert it by opening it in Preview and saving it as a JPEG.. If you don’t have your replacement image yet, you can download some nice ones from InterfaceLift.
Now, move your replacement image into the CoreServices folder. You’ll need to authenticate it by entering your password, and that’s it! The next time you log in, you should see your new login background.
Changing the Background with Loginox
If this method is too tedious for you, there’s a freeware application called Loginox that will do the same thing. It looks like this:
Using it is simple: Just drag your replacement image onto the New Login Image panel, click “Set new Login image”, and you’re done!