Function Set-WallPaper($Value){
    Invoke-WebRequest "https://motd.ping-mee.de/wallpaper.png" -OutFile "$($value)wallpaper.png"
    Set-ItemProperty -path 'HKCU:\Control Panel\Desktop\' -name wallpaper -value "$($value)wallpaper.png"
    rundll32.exe user32.dll, UpdatePerUserSystemParameters
}

Set-WallPaper -value "C:\temp\"