C#圖片無損壓縮

/引用命名空間
using System.Drawing.Imaging;
using System.Drawing;
using System.Drawing.Drawing2D;

#region GetPicThumbnail      /// <summary>      /// 無損壓縮圖片      /// </summary>      /// <param name="sFile">原圖片</param>      /// <param name="dFile">壓縮後保存位置</param>      /// <param name="dHeight">高度</param>      /// <param name="dWidth"></param>      /// <param name="flag">壓縮質量 1-100</param>      /// <returns></returns>        public  bool  GetPicThumbnail( string  sFile, string  dFile, int  dHeight, int  dWidth, int  flag)      {          System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile);            ImageFormat tFormat = iSource.RawFormat;            int  sW = 0, sH = 0;            //按比例縮放            Size tem_size = new  Size(iSource.Width, iSource.Height);                if  (tem_size.Width > dHeight || tem_size.Width > dWidth) //將**改爲c#中的或者操做符號          {                if  ((tem_size.Width * dHeight) > (tem_size.Height * dWidth))              {                    sW = dWidth;                    sH = (dWidth * tem_size.Height) / tem_size.Width;                }                else              {                    sH = dHeight;                    sW = (tem_size.Width * dHeight) / tem_size.Height;                }            }            else          {                sW = tem_size.Width;                sH = tem_size.Height;            }            Bitmap ob = new  Bitmap(dWidth, dHeight);            Graphics g = Graphics.FromImage(ob);            g.Clear(Color.WhiteSmoke);            g.CompositingQuality = CompositingQuality.HighQuality;            g.SmoothingMode = SmoothingMode.HighQuality;            g.InterpolationMode = InterpolationMode.HighQualityBicubic;            g.DrawImage(iSource, new  Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);            g.Dispose();            //如下代碼爲保存圖片時，設置壓縮質量            EncoderParameters ep = new  EncoderParameters();            long [] qy = new  long [1];            qy[0] = flag; //設置壓縮的比例1-100            EncoderParameter eParam = new  EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);            ep.Param[0] = eParam;            try          {                ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();                ImageCodecInfo jpegICIinfo = null ;                for  ( int  x = 0; x < arrayICI.Length; x++)              {                    if  (arrayICI[x].FormatDescription.Equals( "JPEG" ))                  {                        jpegICIinfo = arrayICI[x];                        break ;                    }                }                if  (jpegICIinfo != null )              {                    ob.Save(dFile, jpegICIinfo, ep); //dFile是壓縮後的新路徑                }                else              {                    ob.Save(dFile, tFormat);                }                return  true ;            }            catch          {                return  false ;            }            finally          {                iSource.Dispose();                ob.Dispose();            }            }      #endregion