7Log allows you to change your background easily. All really have do is select the image you wish to use. The only restriction is that must be a jpg the image you wish to use.
It installs the correct registry files, creates the necessary folders and sends your favorite .jpg images to become your login screen background. And if you want the original login back, its just a click away.
But what makes this program better than any proprietary(i.e you have to pay for) program you can find, is that this program is open sourced! And programmers are free to edit the program any way they wish as long as they give me credit for the original coding.

Requirements:
* .NET Framework
* Admin Privileges

The license of this software is Free, you can free download and free use this system utility software.