c#.net 生成清晰縮略圖

  public void imgsize()
         {
             //本例中假定了兩個變量：
 
             String src = "c:/myImages/a.jpg";   //源圖像文件的絕對路徑
             String dest = "c:/myImages/a_th.jpg";    //生成的縮略圖圖像文件的絕對路徑
 
             int thumbWidth = 132;    //要生成的縮略圖的寬度
             int thumbHeight = 100;   //要生成的縮略圖的高度
             System.Drawing.Image image = System.Drawing.Image.FromFile(src); //利用Image對象裝載源圖像
 
             //接著創建一個System.Drawing.Bitmap對象，並設置你希望的縮略圖的寬度和高度。
             int srcWidth = image.Width;
             int srcHeight = image.Height;
             Bitmap bmp = new Bitmap(thumbWidth, thumbHeight);
 
             //從Bitmap創建一個System.Drawing.Graphics對象，用來繪制高質量的縮小圖。
             System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp);
 
             //設置 System.Drawing.Graphics對象的SmoothingMode屬性為HighQuality
             gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 
             //下面這個也設成高質量
             gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
 
             //下面這個設成High
             gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 
             //把原始圖像繪制成上面所設置寬高的縮小圖
             System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(0, 0, thumbWidth, thumbHeight);
             gr.DrawImage(image, rectDestination, 0, 0, srcWidth, srcHeight, GraphicsUnit.Pixel);
 
             //保存圖像，大功告成！
             bmp.Save(dest);
 
             //最後別忘了釋放資源
             bmp.Dispose();
             image.Dispose();
         }