Download and unzip SP.

The readme.txt file contains:

                              sp                              ===============================================================================                              sp.exe sets your Windows desktop wallpaper and background colour.  It also                              turns off Active Desktop, enables centered wallpaper rather than tiled, and                              turns off wallpaper stretching if enabled.                              Use it like:                              sp.exe FFFFFF wallpaper.bmp                              The "FFFFFF" is the hex value for the colour white - it's comprised of three                              hex values of FF, FF and FF for Red, Green and Blue respectively.  In case you                              don't know how hexadecimal works, some common colour values are listed below:                              000000 black                              FFFFFF white                              FF0000 red                              00FF00 green                              0000FF blue                              FFFF00 yellow                              00FF00 magenta                              00FFFF cyan                              808080 grey                              The final parameter is the path to the bitmap to be used as the wallpaper.                              This has to be a bmp file - we turn off Active Desktop remember!                              -------------------------------------------------------------------------------                              Copyright Tom Revell, tom.revell@zhornsoftware.co.uk                              Zhorn Software, http://www.zhornsoftware.co.uk/