把image转换为byte[]

System.IO.MemoryStream Ms = new MemoryStream();
                    this.pcbEquipment.Image.Save(Ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] img = new byte[Ms.Length];
                    Ms.Position = 0;
                    Ms.Read(img, 0, Convert.ToInt32(Ms.Length));
                    Ms.Close();