Change wallpaper from today screen

http://social.msdn.microsoft.com/Forums/en-US/vssmartdevicesnative/thread/6bb27f46-7232-4322-9236-37b555c0369e?prof=required
[code]
    #define WATERMARK_TODAY         1    
    #define WATERMARK_TODAYFULL 2
    typedef bool (*LPF_SHSetAsWatermark)(HWND hWnd, LPCWSTR lpszFile, int iWhich, DWORD* pdwAlpha);

    HMODULE hModule = LoadLibrary(L"aygshell.dll");
    if (hModule)
    {
        LPF_SHSetAsWatermark pSHSetAsWatermark = (LPF_SHSetAsWatermark)GetProcAddress(hModule, (LPCWSTR)169);
        if (pSHSetAsWatermark)
        {            
            DWORD dwAlpha = 0;
            bool ret = pSHSetAsWatermark( NULL, L"\\My Documents\\내 그림\\Smoke1.jpg",WATERMARK_TODAYFULL, &dwAlpha);        
        }
    }
[/code]