/// 

/// Converts an Image to Icon - Supports Image Size upto 128x128
/// 

/// Filename of the Image to convert
private void Image2Icon(string fileName)
{
    //Creats filename with ico extention
    string newFileName = Path.ChangeExtension(fileName, ".ico");
    //Loading the File to the Bitmap
    using (Bitmap bitMap = Image.FromFile(fileName,true) as Bitmap)
    {
        using (Icon icon = Icon.FromHandle(bitMap.GetHicon()))
        {
            //Creating the Icon file and Writing the content
            using (Stream stream = File.Create(newFileName))
            {
                icon.Save(stream);
            }
        }
    }
}