How To Change the Mac OS X Lion Login Screen Background

Are you getting tired of that same gray pattern at your Mac OS X Lion login screen? Have you ever wondered how to go about changing that? Have you toyed and fiddled for hours trying to figure it out?

This simple how-to guide will change this:

To something like this:

Before we do anything, you will want to make a backup of your files, and specifically, the file we’ll be working with. Since we are working with System files, it is also recommended that you have a good idea of the Mac Operating System, as well as image types and formats before proceeding. As long as you do, these next few short steps will have your new Login Screen up and running in no time!

So let’s get started!

1) First, you will need to open a new Finder window. Inside the: System/Library/Frameworks/AppKit.framework/Versions/C/Resources directory is an image file called: “NSTexturedFullScreenBackgroundColor.png“. This is the file that will be working with.
2) Make a copy of this file and save it to your desktop, just so you have it in case something doesn’t go quite right.
3) It is important to note that in order for this to work, the image you chose will have to meet certain criteria:

1. It must be saved as a PNG file.
2. It MUST be in a resolution of 72 pixels per inch. If not, the file will be distorted and repeated on the Login screen, and it will not be to your liking! If you are using Photoshop, the easiest way to check is to click “Image” from the top menu, and click “Image size…”. This will show you the current specifications for your image. As long as these specs match everything we go over in this section, you should not have any issues.
3. Your image must match the screen resolution you currently have set. For this example, my screen resolution is 1680×1050, and so to is my image. To find your screen’s resolution, click on the Apple menu and click “System Preferences”. From there, click the “Displays” icon, and your current resolution will be highlighted.
4. Your image will need to be saved with the exact name as the file you will be replacing. In other words, it needs to be saved EXACTLY as shown (with caps in the same spots): NSTexturedFullScreenBackgroundColor.png. If it is not saved exactly as shown, it will not work.

4) Once you have located the “NSTexturedFullScreenBackgroundColor.png“, you will want to replace it with the image you desire. Drag your desired image into the directory.
5) Since we are working with system files, you will then be asked to Authenticate. Once you have, you will be asked to enter your password. Once this step is complete, and you can see that the file has successfully copied, you can now log out or restart. When you’re brought back to the login screen, you will see your new image!

That’s all there is too it!