Change guest account photo in Mavericks? In Mavericks, how do you change the user account photo to something other than that gray silhouette?  

I've searched for an answer to this question and it seems people figured it out in Mountain Lion and earlier, but not Mavericks as far as I can find.  I'm using OS X 10.9.4.  Thanks.
The image is located at the following location. Change it and reboot.

/System/Library/PrivateFrameworks/LoginUIKit.framework/Versions/A/Frameworks/LoginUICore.framework/Versions/A/Resources/GuestUser.png


GuestUser@2x.png is the image used for Retina displays