Mac OS X 10.7.4 has more than just the new version of Safari; it comes with added support for RAW images and fixes quite a number of issues, including one with the Reopen windows when logging back in option. One of the many things you may have experienced after upgrading to 10.7.4 is that the login screen is no longer the customized one that you had. For those of you who tried Mac tweakers like Deeper and Loginox (which are the ones that we tried, to no avail), they failed to change the login background. Did OS X 10.7.4 break Mac tweakers? Not exactly, it’s just changed where it keeps the background files, and is one reason why you are having difficulty changing the login background. Here’s how you can restore it to what it was before the upgrade.
Changing the login screen background requires nothing more than moving a few image files around and renaming them. The tricky part is to know where to look for these files. Go to the following folder and find the file named applelinen.png.
Replace this file with whatever background image you want to set, and rename your file appleLinen. You will need administrative rights to make this change, and should use a 1400×900 image for best results, although it will depend on your display size as well. The image should be in PNG format. Once you’ve made this change, lock your screen and your new background will replace the default one.
It is likely that Lion tweaking tools will catch up to this change and have an update for it soon, but if you can’t wait that long and staring at the default login background is straining your eyes, you can change it in a few seconds.
Update: Both Deeper and Loginox has released a new version that supports OS X 10.7.4