Change the Mission Control Background Wallpaper Image in Mac OS X Lion

It’s time to customize the appearance of Mac OS X 10.7 again. We recently showed you how to change Dashboards wallpaper image from that Lego-like pattern to anything else, and then we showed you how to change Launchpads folder background pattern to your choice. Next up is Mission Control’s background image, say goodbye to Linen and hello to whatever wallpaper you want to see.

Pick a New Mission Control Background Image and Convert it to PNG
First up, you need to pick a PNG file you want to set as the new Mission Control background. I’m mildly obsessed with iClouds t-shirt background but for the purpose of this walkthrough I’ll use a more obvious change of some coral reef. The image file must be a PNG and it must be named “defaultdesktop.png”, Preview makes it easy to convert or export any image as a PNG:

• Select the File menu and navigate to “Export”
• Choose “PNG” as the filetype and save the image name as “defaultdesktop.png”

Note: you can choose a repeating pattern image or a large wallpaper, if you choose a large wallpaper make sure it at least matches your screen resolution or it can look awful.

Got your image saved? Great. Now we can proceed to customization.

How to Change Mission Controls Background Image

The gist of this tip is similar to changing Dashboard and Launchpad, and you’ll have to dig around in some system files. It’s not complicated, just follow the steps and be sure to make a backup of the file you will replace.

• Hit Command+Shift+G to bring up the “Go To Folder” window, and point at the following URL:

/System/Library/CoreServices/Dock.app/Contents/Resources/

• Locate the existing “defaultdesktop.png” file and make a copy of it – this is important because it allows you to revert your changes. Either drag the existing file to the desktop, rename it to “defaultdesktop-backup.png” or whatever, just be sure you back it up
• Now locate your own previously saved customized “defaultdesktop.png” and drag that file into the opened Resources folder, you will need to authenticate with the admin password in order for the change to take effect



• Next up you have to kill the Dock to relaunch it, so open the Terminal (/Applications/Utilities/) and type the following:

killall Dock

• Give a three-fingered upward swipe and enjoy your new Mission Control background image

The image you pick is a matter of personal taste, but after using the somewhat chaotic coral image in the screenshot up top I quickly went to a more subtle pattern – the repeating iCloud beta pattern, of course.

Don’t miss our other OS X Lion tips while you’re at it.