在C#中      
 
   图片到byte[]再到base64string的转换：
 
               Bitmap bmp = new Bitmap(filepath);
                 MemoryStream ms = new MemoryStream();
                 bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                 byte[] arr = new byte[ms.Length];
                 ms.Position = 0;
                 ms.Read(arr, 0, (int)ms.Length);
                 ms.Close();
             string     pic = Convert.ToBase64String(arr);
 
 
 
 base64string到byte[]再到图片的转换：
 
                      byte[] imageBytes = Convert.FromBase64String(pic);
                     //读入MemoryStream对象
                     MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
                     memoryStream.Write(imageBytes, 0, imageBytes.Length);
                     //转成图片
                     Image image = Image.FromStream(memoryStream);
 
 
 
现在的数据库开发中：图片的存放方式一般有CLOB:存放base64string，BLOB：存放byte[]