using System;

using System.Text.RegularExpressions;

public class Program

{

    //http://stackoverflow.com/questions/37533049/using-regular-expression-on-string-for-use-in-c-sharp/37533189#37533189

    public static void Main()

    {

        string data = "{ns:\"images\"," + 

            "k:\"5127\"," + 

            "mid:\"A04F21EB77CF61E10E43BA33CF1986CA44357448\"," + 

            "md5:\"e2987d19c953bd836ec8fd2e0aa8492\"," + 

            "surl:\"http://someURLIdontwant/\"," + 

            "imgurl:\"http://THISISTHEURLINEED.jpg\"," + 

            "tid:\"OIP.Me2987d199c953bd836ec8fd2e0aa8492H0\"," + 

            "ow:\"300\"," + 

            "docid:\"608010036892077154\"," + 

            "oh:\"225\"," + 

            "tft:\"49\"}";

        string url = Regex.Match(data, "imgurl:\"(.*)\",tid").Groups[1].Value;

        Console.WriteLine(url);

    }

}