Here is a easy way to change the Windows 7 logon screen without needed to hack any files or use any third party software.
First of all you will need the image that you want to use as the logon screen. This file should be called backgroundDefault.jpg and be no larger than 256 Kb. I recommend resizing it to the default resolution of your monitor. If you are not sure what this is try 1024 x 768 for 4:3 monitor 1440 x 900 for a 16:9 monitor. Other resolution might work but these two option i know for sure work. The really important part is that it is smaller than 256Kb.
(How to edit a image is beyond the scope of this article)
Now to make the image appear on the logon screen.
Part one, make a small change to the registry.
1. Click the windows start button and type regedit and press enter
2. (Be careful in regedit as you can mess up your install of windows if you are not careful, Although what we are doing is pretty safe)
3. Inside regedit navigate to HKEY_LOCAL_MACHINE\ SOFTWARE\ Microsoft\ Windows\ CurrentVersion\ Authentication\ LogonUI\ Background
4. On the right you will see (Default) if you have another entry bellow (Default) called OEMBackground then double click on it and change it’s value to 1 and skip to step 8.
5. If you do not have the OEMBackground entry then do steps 6, 7 and 8.
6. Right click under (Default) in the blank white area and select New DWORD (32-bit) Value
7. Name it OEMBackground and then double click it to change it’s value. Enter 1 for the value.
8. Close regedit.
Part two, put the image file in the right location on the Hard Drive.
1. Click the Start menu, type Windows and click on Windows Explorer to run it.
2. On the left panel of Windows Explorer click Computer then on the right Double Click Your Local C: drive.
3. Navigate to C:\Windows\System32\oobe
4. Click New folder and call it info
5. Double click on info to enter that folder.
6. Click New Folder again and call this one backgrounds
7. Copy your backgroundDefault.jpg into the backgrounds directory.
8. This is a protected area of the Hard Drive so you will be prompted to to confirm this. Just click continue.
Reboot to see your new logon screen with your custom image.
** If it does not work then make sure the image is smaller than 256k and either 1440 x 900 or 1024 x 768. You might have to lower the compression on the JPG to make it small enough.
** If you need to edit the image you will need to copy it somewhere else first and then edit and copy it back. This is a protected area of the Hard Disk and directly editing is not allowed.
If you have any problem or have questions please leave a comment bellow.