string test = "<img src=http://images.gg-art.com/auction/images/45/45360424.jpg border=0><br>李瑞清 行书七言对联洒银笺本</a>";
string url = string.Empty;
string text = string.Empty;
Match m = Regex.Match(test, @"<img.*?src=(['""]?)(?<url>[^'""\s>]*)\1[^>]*>(?<text>[\s\S]*?)</a>", RegexOptions.IgnoreCase);
if (m.Success)
{
url = m.Groups["url"].Value;
text = Regex.Replace(m.Groups["text"].Value, "<[^>]*>", "");
}
Match m = Regex.Match(yourStr, @"<img.*?src=(['""]?)(?<url>[^'""\s>]*)\1[^>]*>(?<text>[\s\S]*?)</a>", RegexOptions.IgnoreCase);
if (m.Success)
{
url = m.Groups["url"].Value;
text = Regex.Replace(m.Groups["text"].Value, "<[^>]*>", "");
}