上传图片转字节保存到数据库，数据库读出字节转换为图片方法

　　  byte[] byteimg = File.ReadAllBytes(@"\zk.jpg");

　　　/// <summary>
        /// 将图片转为字符数组
        /// </summary>
        /// <param name="img"></param>
        /// <returns></returns>
        public  byte[] ImageToByte(System.Drawing.Image img)
        {
            MemoryStream ms = new MemoryStream();
            byte[] imagedata = null;
            img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            imagedata = ms.GetBuffer();
            return imagedata;
        }

/// <summary>
        /// 将字符数组转为图片
        /// </summary>
        /// <param name="byt"></param>
        /// <returns></returns>
        public  System.Drawing.Image ByteToImage(byte[] byt)
        {
            MemoryStream ms = new MemoryStream(byt);
            System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
            return img;
        }