asp.net 过滤图片标签的正则

public static string replaceImgUrl(string html) 
{ 
if (html == null) 
return ""; 

System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex(@"\<img[^\>]+\>", System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
html = regex.Replace(html, ""); //过滤frameset 
return html; 
}