A lot of people have complained that the login screen is too bland and boring in Lion - it now sports Apple’s new favourite grey linen texture. Fortunately, it’s not to tricky to make some customisations. It is possible to change the background, add a custom welcome message and display system stats. Find out how below.

Changing the background

In Lion, the background used for the login screen is located at

/System/Library/Frameworks/AppKit.framework/Versions/C/Resources/

The easiest way to get to this folder is to choose Go to Folder in the Go menu while in the Finder. Then just copy and paste in the above line and click Go. The image that is used for the background is NSTexturedFullScreenBackgroundColor.png. You can replace this with any other image, and as long as you give it exactly the same name, it will be used for the login screen background. Before you make any changes, make sure you make a copy of the original file somewhere safe so you can go back to it if you want.

You’ll notice that the image is only a small 256x256 pixel square — this is because it is automatically tiled across the screen. If you want to use a similar type of texture, any size image is fine. However, if you would like to use a full size image without tiling, you need to make sure the image dimensions exactly match your screen and the resolution is 72 dpi. Either way, it must also be in PNG format like the original. It’s pretty simple to use Preview to adjust any image to the correct size and format.

Display a short message

Before Lion, displaying a message on the login screen was a complicated process that involved entering commands into the Terminal. Luckily, Apple have now added an easy way to set a message using System Preferences. To do this, go to the Security & Privacy preference pane, and under the General tab, tick the checkbox Show a message when the screen is locked then add your message. Only about the first 200 characters you enter will be displayed, so make your message short and sweet.

Display system stats

In older versions of Mac OS X, simply clicking on your computer name in the login window would cycle through displaying lots of useful system information. Unfortunately this feature has been removed in Lion, but you can bring it back to a certain extent. Open up Terminal (located in Applications/Utilities), paste in the following line and press Return:

sudo defaults write /Library/Preferences/com.apple.loginwindow AdminHostInfo HostName

Now when on the login screen, clicking on the time in the top right will cause the computer name to appear, followed by the OS version and build number, followed by the IP address.

Display a login banner

Apple has a great article over on their support site on how to display an agreement window where users must read and click Accept before logging into the computer. This is really useful for people who manage lots of Macs in a school or company with an “Acceptable Use Policy” that all users must agree to.

To do this, just create a file in TextEdit that contains whatever text you want to display. You can embed images and use whatever text styling you want. Once you are done, save the file with the name PolicyBanner in the Security folder in the Library in Macintosh HD.