ms = new MemoryStream();

final_image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

Thumbnail thumb = new Thumbnail(thumbnail_id, ms.GetBuffer()  );

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.IO;

using System.Collections.Generic;



public partial class upload : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        

        System.Drawing.Image thumbnail_image = null;

        System.Drawing.Image original_image = null;

        System.Drawing.Bitmap final_image = null;

        System.Drawing.Graphics graphic = null;

        MemoryStream ms = null;



        try

        {

            // Get the data  得到上传的文件

            HttpPostedFile jpeg_image_upload = Request.Files["Filedata"];



            // Retrieve the uploaded image  把上传文件转化为 Image

            original_image = System.Drawing.Image.FromStream(jpeg_image_upload.InputStream);









            // Calculate the new width and height 下边一整段，都是计算长宽的,具体算法没有深究

            int width = original_image.Width;     //原始宽度

            int height = original_image.Height;   //原始长度

            int target_width = 200;

            int target_height = 200;

            int new_width, new_height;



            float target_ratio = (float)target_width / (float)target_height;  //目标 宽长比

            float image_ratio = (float)width / (float)height;   //原始  宽长比



            if (target_ratio > image_ratio)   //计算出新的长宽。 

            {

          &n