string tempStr = File.ReadAllText(@"C:\Documents and Settings\Administrator\桌面\Test.txt", Encoding.GetEncoding("GB2312"));//读取tx

                string pattern = @"(?<=\()[^)]+(?=\))";

                string[] result = Regex.Matches(tempStr, pattern).Cast<Match>().Select(a => a.Value).ToArray();
                /*
                 *         [0]    "../images/changpinlist_01.jpg"    string
                        [1]    "../images/changpinlist_02.jpg"    string
                        [2]    "../images/changpinlist_03.jpg"    string

                 */

------解决方案--------------------
C:\Css.txt是你的文本内容

C# code

string CssStr = File.ReadAllText(@"C:\Css.txt", System.Text.Encoding.GetEncoding("GB2312"));
                List<string> list=new   List<string>();
                string pattern = @"(?is)(?<=\()[^()]*?(?=\))";
               foreach(Match m in Regex.Matches(CssStr , pattern))
              {
                    list.Add(m.Value);//结果接在list中
              }