Those of you who have been editing your login background since 10.7 through to 10.7.3 would have noticed that upgrading to 10.7.4 broke the custom login background. This is because Apple have changed the way in which this background is applied, as well as the location.
If you would prefer to do this via GUI then you now can, with the excellent LoginOX app.
NOTE: LoginOX resizes the image to match the SYSTEM display. So if you have two displays, change over to the larger display before using it, set your background and change back otherwise the background will be to small and it will tile.
Proper Method
The new file (named 267.png) is now contained in a .bin file in the following location:
/System/Library/PrivateFrameworks/CoreUI.framework/Versions/A/Resources/
Make a copy of the SArtFile.bin file and paste it to your desktop.
To extract the files from this .bin, you will need a little program called “SArtFileTool” – you can download this file here as well as via the MacThemes website.
Extract this file to your desktop, and you will have a folder on your desktop named “SArtFileTool”. Move the copy of the “SArtFile.bin” in to the same folder. Your desktop folder will then contain the following files:
Open Terminal and change the directory to the folder on your desktop:
cd /Users/username/Desktop/SArtFileTool
Followed by this command to extract the .bin files:
./sartfiletool -d SArtFile.bin artfiles
This will place a new folder called “art files” inside the “SArtFileTool” folder on your desktop.
The file that the login window is using is:
267.png
You can replace this .png with the image you want to use. In my tests I kept the image the same dimensions as the original (256 x 256).
When you are done, you now need to put the files back in a .bin file with the following command:
./sartfiletool -e artfiles SArtFile.bin SArtFile.new.bin
This will create a new .bin file in the folder called “SArtFile.new.bin” – you should rename this file “SArtFile.bin” and place it back in the original location. Though you have to delete the original file our first, trying to replace it will fail saying that the file is in use. Make a backup of the original .bin file if you ever want to revert.
I just used a custom .png I made in Photoshop from a pattern found on the internet. Here is my file which you are free to use:
I can also confirm that you can use an image to fill the entire screen instead of tiling. I created a custom background the size of my resolution 1440×900 and it worked fine. If you are having problems with scrambling, then make the image from scratch. For example, in Photoshop create a new image, with the dimensions you want and a transparent background. Don’t at any point Flatten the image. When saving, do so as PNG file type and uncheck Save: “As Copy”.