First, download
ResHack (Resource Hacker). Open the EXE.
Open an explorer window and navigate to C:\Windows\System32\. Find the file imageres.dll. Youll need to first take ownership of the file, and then give yourself full permissions. If you dont know how to do that, Google it or something, Im not gonna hold your hand through this.
After youve taken permissions, open it in ResHack. Look under the IMAGE resources and find your desktop resolution that corresponds to a resource number:
5031 = 1280×1024
5032 = 1280×960
5033 = 1024×768
5034 = 1600×1200
5035 = 1440×900
5036 = 1920×1200
5037 = 1280×768
5038 = 1360×768
5039 = 1024×1280
5040 = 960×1280
5041 = 900×1440
5042 = 768×1280
5043 = 768×1360
Note: If your resolution is not listed, you should use 5031. The image will stretch.
Find the one that matches your resolution, and open that numbered folder. Right click on the 1033″ and select Replace Resource. Browse to another image (preferrably of the same size
I dont know what Vista does as far as stretching/tiling the image). When it asks you for the resource info, type this in:
Resource Type: IMAGE
Resource Name: 50xx (your screen resolution from above, the 50__ number)
Resource Language: 1033
Your new image should appear on-screen. Before you save it, go back to /System32/ and rename your original imageres.dll to something like image.res.dll~. After that, back in ResHack, choose File > Save As, and save it as C:\Windows\System32\imageres.dll. Close ResHack, try a Windows+L, and see if you see your image. If you do, congrats, you dont have to look at Microsofts crappy abstract wisp art. If not
something went wrong. Try again, or
go cry or something.