C# 圖片縮減

/// <summary>
        /// 縮小圖片
        /// </summary>
        /// <param name="strOldPic">源圖檔案名稱(包括路徑)</param>
        /// <param name="strNewPic">縮小後儲存為檔案名稱(包括路徑)</param>
        /// <param name="intWidth">縮小至寬度</param>
        /// <param name="intHeight">縮小至高度</param>
        public void SmallPic(string strOldPic, string strNewPic, int intWidth, int intHeight)
        {

            System.Drawing.Bitmap objPic, objNewPic;
            try
            {
                objPic = new System.Drawing.Bitmap(strOldPic);
                objNewPic = new System.Drawing.Bitmap(objPic, intWidth, intHeight);
                objNewPic.Save(strNewPic);

            }
            catch (Exception exp) { throw exp; }
            finally
            {
                objPic = null;
                objNewPic = null;
            }
        }