/// <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();
    }