//写入到响应流smallimg.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); //保存到本地smallimg.Save(context.Request.MapPath(smallimgname));

//将表单中的文件用字节数组的形式发送到制定的url地址中
WebClient wb = new WebClient();wb.UploadData(urladdress, FileUpload1.FileBytes);

//接收传来的文件
  using (FileStream fs = File.OpenWrite(@"h:\" + id + ext))
      {
        //context.Request.InputStream就是Web服务器wc.UploadData第二个参数的数据流
          context.Request.InputStream.CopyTo(fs);
      }
//保存图片数据 验证码中提取
System.IO.MemoryStream stream = new System.IO.MemoryStream();
image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
//输出图片流
context.Response.Clear();
context.Response.ContentType = "image/jpeg";
context.Response.BinaryWrite(stream.ToArray());