winform求高速缩略图算法！（相机照片质量很高要去速度）
相机的照片提取缩略图 质量太高所以凡是用自带加载的话效率根本上不去
现在求高手想个办法如何高速生成缩略图（质量可无视）最好是微软打印向导生成缩略图的速度请高手帮帮忙谢谢！


[解决办法]

        private Bitmap GetThumbnailImage(string s_FilePath, int x, int y)
        {
            using (Bitmap OriginalMap = new Bitmap(s_FilePath))
            {
                Bitmap Map = new Bitmap(x, y, PixelFormat.Format24bppRgb);
                Rectangle Mrect = new Rectangle(0, 0, x, y);
                BitmapData MbmpData = Map.LockBits(Mrect, ImageLockMode.ReadWrite, Map.PixelFormat);

                int x_Width = OriginalMap.Width;
                int y_Height = OriginalMap.Height;
                Rectangle rect = new Rectangle(0, 0, x_Width, y_Height);
                BitmapData bmpData = OriginalMap.LockBits(rect, ImageLockMode.ReadWrite, OriginalMap.PixelFormat);

                int stribe = bmpData.Stride;
                int Mstribe = MbmpData.Stride;

                unsafe
                {
                    try
                    {
                        byte* ptr = (byte*)(bmpData.Scan0);
                        byte* Mptr = (byte*)(MbmpData.Scan0);

                        for (int i = 0; i < y_Height; i++)
                        {
                            for (int j = 0; j < x_Width; j++) 
 
                            {
                                int x_zoom = (int)x * j / x_Width;
                                int y_zoom = (int)y * i / y_Height;

                                Mptr[y_zoom * Mstribe + x_zoom * 3] = ptr[0];
                                Mptr[y_zoom * Mstribe + x_zoom * 3 + 1] = ptr[1];
                                Mptr[y_zoom * Mstribe + x_zoom * 3 + 2] = ptr[2];

                                ptr += 3;
                            }
                            ptr += stribe - x_Width * 3;
                        }
                        OriginalMap.UnlockBits(bmpData);
                        Map.UnlockBits(MbmpData);
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message, "Information");
                    }
                }
                return Map;
            }
        }