how do I change the login background image in yosemite?

I believe I have successfully proven that the login background choice Yosemite makes is BROKEN!

In my case it defaulted to the desktop image of a test account I use about 1/10 the time I use my primary account.

In addition I found after DELETING that account, Yosemite is keeping the now non existent account's desktop picture as the login background...

This is inspire of the fact that both the user and the user folder tied to it no longer exist...

Apple either needs to change the way this image is assigned, because the current method is open to too many problems...

I stumbled across the answer, and yes, you CAN change it!

After setting a desktop a file gets created under the following path:

/Library/Caches/com.apple.desktop.admin.png

This is a blurred copy of your desktop, and it's what is used as the login background.

If you replace this with a different image, it will use that in it's place. I would recommend getting info on the replacement & checking locked, this should prevent Mac OS X from changing back again...

This is what I just did and it works, thank you for the tip.

The only problem is that my picture in the login screen is somehow "hazy" or "overcast". I checked that the original picture com.apple.desktop.admin.png was still with full definition and it was.

Any clue to solve this ?

I don't think there's any way to solve this but its definitely a workable solution for now and beats the crap blurriness we had before. Many thanks Bobby T!

Hi,

How do you 'replace' it?

Thanks

Login Screen – change background