Change Your Mac's Lock Screen Image

I worked at Interactive Intelligence before before it was acquired by Genesys and IT had put a custom lock screen image on all the Macs. Well, now that the transition is mostly through I figured it was about time that custom lock screen went away.

It took a while find the instructions on how to do it, but I finally found them on OSX Daily.

What you need to do is replace the file at /Library/Caches/com.apple.desktop.admin.png.

The image you replace it with needs to be a PNG and you probably want something high resolution, I went with one of the built-in wallpapers that comes on a Mac, found here: /Library/Desktop Pictures.

Here are the steps I went through:

# Backup the existing image
sudo cp /Library/Caches/com.apple.desktop.admin.png /Library/Caches/com.apple.desktop.admin.bak.png

# The existing image was locked for me, so I had to unlock it
# You may not need this step
sudo SetFile -a l /Library/Caches/com.apple.desktop.admin.png

# Copy the new image in, I had the new image on my desktop
sudo cp ~/Desktop/com.apple.desktop.admin.png /Library/Caches/com.apple.desktop.admin.png