This is the easiest and Simplest Way of Changing your login screen
1.Download This File http://www.mediafire.com/?lupa48gu6cc3exd
2.Extract it using Winrar
3.Open it
4.Choose the picture you want at login.
If your Picture Size is big it will Automatically Convert it to the size wanted.
Now the Default Windows Picture will change and will be the picture you chose
Works with Windows 7