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">壓縮後儲存位置</param>    /// <param name="dHeight">高度</param>    /// <param name="dWidth"></param>    /// <param name="flag">壓縮品質 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**改成c#中的或者操作符號        {            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();        //以下代碼為儲存圖片時，設定壓縮品質        EncoderParameters ep = new EncoderParameters();        long[] qy = new long[1];        qy[0] = flag;//設定壓縮的比例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