图片导入导出数据库

        private Stream stream=new Stream();
        Bitmap bp=new Bitmap();
        /// <summary>
        /// 向数据库中导入图片
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog of = new OpenFileDialog();
            if (of.ShowDialog() == DialogResult.OK)
            {
                bp = new Bitmap(of.FileName);
                stream=of.OpenFile();//2下面
            }
            string sql = "update h_doctor set xiangPian=?xiangpian where ID="+12;
            using (MySqlConnection conn = new MySqlConnection(mysqlHelp.ConnectionString))
            {
                MySqlCommand cmd = new MySqlCommand(sql, conn);
                byte[] bytes = new byte[stream.Length];
                stream.Read(bytes, 0, (int)stream.Length);
                cmd.Parameters.AddWithValue("?xiangpian", bytes);
                try
                {
                    conn.Open();
                    cmd.ExecuteNonQuery();
                    pictureBox1.Image = bp;
                }
                catch (Exception e1)
                {
                    MessageBox.Show("图片太大！图片支持20K以内");
                }
                finally
                {
                    conn.Close();
                }
                
            }

        }
        /// <summary>
        /// 图片导出
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            string sql = "select xiangpian from h_doctor where ID=" + 12;
            using (MySqlConnection conn = new MySqlConnection(mysqlHelp.ConnectionString))
            {
                MySqlCommand cmd = new MySqlCommand(sql, conn);
                conn.Open();
                MySqlDataReader read = cmd.ExecuteReader();
                if (read.Read())
                {
                    if (read[0].GetType() != typeof(DBNull))
                    {
                        byte[] bs = (byte[])read[0];
                        MemoryStream mem = new MemoryStream(bs);
                        Bitmap bm = new Bitmap(mem);
                        pictureBox1.Image = bm;
                    }
                }
            }
        } 

2、 FileStream fs = File.OpenRead(of.FileName));
            byte[] imageb = new byte[fs.Length];
            fs.Read(imageb, 0, imageb.Length);
            fs.Close();
            SqlCommand com3 = new SqlCommand (sql,con);
            com3.Parameters.Add("@images", SqlDbType.Image).Value = imageb;