高效无损图片压缩方法实现与代码示例

        #region Thumbnail

        /// <summary>
        /// 获取无损压缩图片
        /// </summary>
        /// <param name="sourceFilePath">原图片</param>
        /// <param name="thumFilePath">压缩后保存位置</param>
        /// <param name="width">宽度</param>
        /// <param name="height">高度</param>
        /// <returns>压缩后的新路径</returns>
        public static string GetThumbnailImg(string sourceFilePath, string thumFilePath, int width, int height)
        {
            int flag = 100;
            Image soureImg = Image.FromFile(sourceFilePath);
            ImgThumbnailType type = soureImg.Width > soureImg.Height ? ImgThumbnailType.W : ImgThumbnailType.H;
            return GetThumbnailImg(soureImg, thumFilePath, width, height, flag, type);
        }

        /// <summary>
        /// 获取无损压缩图片
        /// </summary>
        /// <param name="sourceFilePath">原图片</param>
        /// <param name="thumFilePath">压缩后保存位置</param>
        /// <param name="width">宽度</param>
        /// <param name="height">高度</param>
        /// <param name="flag">压缩质量 1-100</param>
        /// <param name="type">压缩缩放类型</param>
        /// <returns>压缩后的新路径</returns>
        public static string GetThumbnailImg(string sourceFilePath, string thumFilePath, int width, int height, int flag, ImgThumbnailType type)
        {