cambiarescritorio.cs

using System;
using System.Runtime.InteropServices;

namespace cambiarescritorio
{
    class Program
    {
        [DllImport("user32.dll")]
        public static extern Int32 SystemParametersInfo(
                       UInt32 action, UInt32 uParam, String vParam, UInt32 winIni);

        public static readonly UInt32 SPI_SETDESKWALLPAPER = 0x14;
        public static readonly UInt32 SPIF_UPDATEINIFILE = 0x01;
        public static readonly UInt32 SPIF_SENDWININICHANGE = 0x02;

        public static void SetWallpaper(String path)
        {
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, path,
                SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE);
        }
        static void Main(string[] args)
        {
            if (args.Length >= 1)
            {
                SetWallpaper(args[0]);
            }
        }
    }
}