代码段1
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System.Drawing.Image image =
System.Drawing.Image.FromFile(originalFilename);
System.Drawing.Size size = GetImageSize(image.Width, image.Height,
information.MaximumDimension);
System.Drawing.Image bitmap = new System.Drawing.Bitmap(size.Width,
size.Height);
System.Drawing.Graphics graphics =
System.Drawing.Graphics.FromImage(bitmap);
graphics.InterpolationMode =
System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
graphics.Clear(information.BackgroundColor);
graphics.DrawImage(image, new System.Drawing.Rectangle(0, 0, bitmap.Width,
bitmap.Height), new System.Drawing.Rectangle(0, 0, image.Width,
image.Height), System.Drawing.GraphicsUnit.Pixel);
graphics.Dispose();


代码段2
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//原始图片名称
string originalFilename = "c:\\222.jpg";
//生成的高质量图片名称
string strGoodFile = "c:\\222-small-good.jpg";
//生成的低质量图片名称
string strBadFile = "c:\\222-small-bad.jpg";
//缩小的倍数
int iScale = 3;

//从文件取得图片对象
System.Drawing.Image image = System.Drawing.Image.FromFile(originalFilename);
//取得图片大小
System.Drawing.Size size = new Size(image.Width / iScale , image.Height / iScale);
//新建一个bmp图片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(size.Width,size.Height);
//新建一个画板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空一下画布
g.Clear(Color.Blue);
//在指定位置画图
g.DrawImage(image, new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
new System.Drawing.Rectangle(0, 0, image.Width,image.Height),
System.Drawing.GraphicsUnit.Pixel);
//保存高清晰度的缩略图
bitmap.Save(strGoodFile, System.Drawing.Imaging.ImageFormat.Jpeg);
//取得原图像的普通缩略图
System.Drawing.Image img = image.GetThumbnailImage(image.Width / iScale, image.Height / iScale, null, IntPtr.Zero);
//保存普通缩略图
img.Save(strBadFile, System.Drawing.Imaging.ImageFormat.Jpeg);

g.Dispose();
MessageBox.Show("生成完毕");



俺自己写的一段原图+缩略图代码
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using System;
using System.Collections;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace BSCRM.Shangpin
{
 ///

 /// Shangpin_IMG 的摘要说明。
 ///

 public class Shangpin_IMG : System.Web.UI.Page
 {
  string ImagePath = ConfigurationSettings.AppSettings["ImagePath"]+"\\";
  bool error;
  string src;
  int height,width;
  private void Page_Load(object sender, System.EventArgs e)
  {
   // 在此处放置用户代码以初始化页面
   height=width=0;

   if(Request["h"]!=null&&Request["h"].ToString().Trim()!="")
   {
    height=int.Parse(Request["h"].ToString().Trim());
   }
   if(Request["w"]!=null&&Request["h"].ToString().Trim()!="")
   {
    width=int.Parse(Request["w"].ToString().Trim());
   }
        

   if(Request["src"]!=null)
   {
    src = ImagePath+Request["src"].ToString();
    try
    {
     System.Drawing.Image img = System.Drawing.Image.FromFile(src);

     if(height>0||width>0)
     {
      if(height==0) height=img.Height;
      if(width==0) width=img.Width;
      System.Drawing.Image img2 = img.GetThumbnailImage(width,height,null,IntPtr.Zero);
      img2.Save(Response.OutputStream,img.RawFormat);
      img2.Dispose();
     }
     else
     {
         img.Save(Response.OutputStream,img.RawFormat);
     }

     img.Dispose();
    }
    catch
    {
     error = true;
    }
   }
   else
   {
    error = true;
   }

   if(error)
   {
    Response.StatusCode = 404;
    Response.Write("

HTTP/1.1 404 Object Not Found

");
   }
  }

  #region Web 窗体设计器生成的代码
  override protected void OnInit(EventArgs e)
  {
   //
   // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
   //
   InitializeComponent();
   base.OnInit(e);
  }
  
  ///

  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  ///

  private void InitializeComponent()
  {   
   this.Load += new System.EventHandler(this.Page_Load);
  }
  #endregion
 }
}

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