How to change windows logon background by code

I would like to set programatically a background image for the windows logon screen.

How can I do that ?

Prefered language is C#开发者_运维问答 but I can read other languages and adapt :)

Best regards

Try read this link. http://www.intowindows.com/how-to-change-windows-7-logon-screen-easily-without-using-hacks-tools/ In the program, you must make creating of one directory and copy JPG file to this directory.