public String fixalt(String text)
        {
            Regex reg = new Regex(@"<img[^>]+>");
            MatchCollection matches = reg.Matches(text);
            String src, match;
            for (int i = 0; i < matches.Count; i++)
            {
                match = matches[i].ToString();
                if (match.IndexOf("alt=") < 0)
                {
                    // Use the src info to try to come up with an alt tag that makes sense.
                    if (match.IndexOf("src=") >= 0)
                    {
                        // get everything after the src tag
                        src = match.Substring(match.IndexOf("src=") + 4);
                        // strip out all quotes
                        src = src.Replace("\"", "").Replace("'", "");
                        // end at the first space
                        src = src.Substring(0, src.IndexOf(" "));
                        // grab everything after the last / (don't use path info for the image, just try to get the image name)
                        if (src.IndexOf("/") >= 0)
                        {
                            src = src.Substring(src.LastIndexOf("/")+1);
                        }
                        src = src.Replace(".jpg", "").Replace(".png", "").Replace(".gif", "").Replace("_", " ").Replace("+", " ").Replace("-", " ");
                        text = text.Replace(match, match.Substring(0, match.LastIndexOf(" ")) + " alt=\"" + src + "\" />");
                    }
                    else
                    {
                        text = text.Replace(match, match.Substring(0, match.Length - 1) + " alt=\"contentimage\">");
                    }
                }
            }

            return text;
        }