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

            //接着創建一個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);

            //最后別忘了釋放資源
            bmp.Dispose();
            image.Dispose();
        }