通过这段代码，我可以从c的wpf中的mysql数据库下载（检索）图像。这个代码我有一个副本https://www.experts-exchange.com/questions/25096053/retrieve-images-in-c-wpf-application-from-sql-server-database.html 网站。但我不知道这些代码是怎么一行一行地工作的。如果有人知道这一点，请帮助。
代码在这里。

string query = "SELECT image_data from image_table WHERE image_id=22";
            MySqlCommand cmd = new MySqlCommand(query, connection);
            MySqlDataReader dataReader = cmd.ExecuteReader();
            while (dataReader.Read())
            {
                Byte[] bindata = (Byte[])dataReader["image_data"];
                MemoryStream strm = new MemoryStream();
                strm.Write(bindata, 0, bindata.Length);
                strm.Position = 0;
                System.Drawing.Image img = System.Drawing.Image.FromStream(strm);
                BitmapImage bi = new BitmapImage();
                bi.BeginInit();
                MemoryStream ms = new MemoryStream();
                img.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
                ms.Seek(0, SeekOrigin.Begin);
                bi.StreamSource = ms;
                bi.EndInit();
                download.Source = bi; 
            }