图片缩放后上传，服务器上只保存缩放后的图片,该如何处理

    /// <summary>    /// 图片缩放    /// </summary>    /// <param name="sourcePath">客户端路径</param>    /// <param name="savePath">保存服务器端路径</param>    /// <param name="w">宽</param>    /// <param name="h">高</param>    public static void ImageChange(string sourcePath, string savePath, int w, int h)    {        System.Drawing.Image _sourceImg = System.Drawing.Image.FromFile(sourcePath);        double _newW = (double)w, _newH = (double)h, t;        if ((double)_sourceImg.Width > w)        {            t = (double)w;        }        else        {            t = (double)_sourceImg.Width;        }        if ((double)_sourceImg.Height * (double)t / (double)_sourceImg.Width > (double)h)        {            _newH = (double)h;            _newW = (double)h / (double)_sourceImg.Height * (double)_sourceImg.Width;        }        else        {            _newW = t;            _newH = (t / (double)_sourceImg.Width) * (double)_sourceImg.Height;        }        System.Drawing.Image bitmap = new System.Drawing.Bitmap((int)_newW, (int)_newH);        System.Drawing.Graphics g = Graphics.FromImage(bitmap);        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;        g.Clear(Color.Transparent);        g.DrawImage(_sourceImg, new Rectangle(0, 0, (int)_newW, (int)_newH), new Rectangle(0, 0, _sourceImg.Width, _sourceImg.Height), GraphicsUnit.Pixel);        _sourceImg.Dispose();        g.Dispose();        try        {            bitmap.Save(savePath, System.Drawing.Imaging.ImageFormat.Jpeg);        }        catch        {        }        bitmap.Dispose();    }