将文件读成byte..

   FileStream fs = new FileStream(@"D:\22-11-46-3-524454584.jpg",FileMode.Open,FileAccess.Read);
   byte[] mydata = new byte[fs.Length];
   int Length = Convert.ToInt32(fs.Length);
   fs.Read(mydata,0,Length);
   fs.Close();
   this.Response.OutputStream.Write(mydata,0,Length);
   this.Response.End();