一般处理程序上传图片压缩图片大小

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Drawing;

namespace CZBK.ItcastProject.WebApp._2015_5_29
{
    /// <summary>
    /// Thumb 的摘要说明
    /// </summary>
    public class Thumb : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            //创建缩略图，定义一个小的画布，将图片画到该画布上，最后保存
            string filePath=context.Request.MapPath("/ImageUpload/water4cb175bc-cd59-42d7-836d-0ba1ed8bf7b5.jpg");
            using (Bitmap map=new Bitmap(50,50))
            {
                using (Image img=Image.FromFile(filePath))
                {
                    using (Graphics g = Graphics.FromImage(map))
                    {
                        g.DrawImage(img,0,0,map.Width,map.Height);
                        string fileName = Guid.NewGuid().ToString();
                        map.Save(context.Request.MapPath("/ImageUpload/thumb"+fileName+".jpg"),System.Drawing.Imaging.ImageFormat.Jpeg);
                        context.Response.Write("缩略图生成成功");
                    }
                }
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}