ASP.NET 生成缩略图片类分享

        /// <summary>
        /// 生成图片缩略图 指定文件路径生成
        /// </summary>
        public static void SaveImage(String fullName, string fileName, int w, int h)
        {
            FileStream fs = new FileStream(fullName, FileMode.Open);
            System.Drawing.Image image = System.Drawing.Image.FromStream(fs, true);
            fs.Close();
            SaveImage(image, fileName, w, h);
        }

        /// <summary>
        /// 生成图片缩略图 指定文件流生成
        /// </summary>
        public static void SaveImage(Stream fs, string fileName, int w, int h)
        {
            Image image = System.Drawing.Image.FromStream(fs, true);
            SaveImage(image, fileName, w, h);
        }

        /// <summary>
        /// 生成图片缩略图 
        /// </summary>
        public static void SaveImage(System.Drawing.Image image, string fileName, int w, int h, int high = 90)
        {
            if (w == 0 && h == 0)
            {
                w = image.Width;
                h = image.Height;
            }
            else if (w > 0 && h > 0)
            {
                if (image.Width > image.Height)
                {
                    if (image.Width > w)
                    {
                        h = (int)(image.Height * ((decimal)w / image.Width));
                    }
                    else
                    {
                        h = image.Height;
                        w = image.Width;
                    }
                }
                else
                {
                    if (image.Height > h)
                    {
                        w = (int)(image.Width * ((decimal)h / image.Height));
                    }
                    else
                    {
                        h = image.Height;
                        w = image.Width;
                    }
                }
            }
            else if (w > 0)
            {
                if (image.Width > w)
                {
                    h = (int)(image.Height * ((decimal)w / image.Width));
                }
                else
                {
                    h = image.Height;
                    w = image.Width;
                }
            }
            else if (h > 0)
            {
                if (image.Height > h)
                {
                    w = (int)(image.Width * ((decimal)h / image.Height));
                }
                else
                {
                    h = image.Height;
                    w = image.Width;
                }
            }

            Bitmap ret = new Bitmap(w, h);

            using (Graphics g = Graphics.FromImage(ret))
            {
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.FillRectangle(Brushes.White, 0, 0, w, h);
                g.DrawImage(image, 0, 0, w, h);
                EncoderParameters parms = new EncoderParameters();
                long[] quality = new long[1];
                quality[0] = high;
                EncoderParameter parm = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
                parms.Param[0] = parm;
                ImageCodecInfo[] arr = ImageCodecInfo.GetImageEncoders();
                ImageCodecInfo ar = null;
                for (int x = 0; x < arr.Length; x++)
                {
                    if (arr[x].FormatDescription.Equals("JPEG"))
                    {
                        ar = arr[x];
                        break;
                    }
                }

                ret.Save(fileName, ar, parms);
                ret.Dispose();
                image.Dispose();
            }
        }