I found this on another site. The following is a copy-paste:
Open your Paint program.
Select Image->Attributes and make your image 2 pixels by 2 pixels.
Select View->Zoom->Custom->800%
Now put black in the lower-left corner, dark gray in the lower-right corner, and light grey in the upper-left.
Like so...
Save it somewhere convenient, then in your display properties, select the bitmap you just made, select 'Center' and Stretch Desktop Wallpaper enabled.
Lovely isn't it?
This works with all kinds of bitmaps, look at this one...
and what it does...
Source
Open your Paint program.
Select Image->Attributes and make your image 2 pixels by 2 pixels.
Select View->Zoom->Custom->800%
Now put black in the lower-left corner, dark gray in the lower-right corner, and light grey in the upper-left.
Like so...
*i11.tinypic.com/5x77d41.jpg
Save it somewhere convenient, then in your display properties, select the bitmap you just made, select 'Center' and Stretch Desktop Wallpaper enabled.
Lovely isn't it?
*i16.tinypic.com/54mklzl.jpg
This works with all kinds of bitmaps, look at this one...
*i11.tinypic.com/61txwf7.jpg
and what it does...
*i10.tinypic.com/53rcv8l.jpg
Source
