using System;

using System.Xml;

using System.Xml.Linq;

using System.Linq;

using HtmlAgilityPack;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var html = @"<div class='media-img'>

    <div class=' searched-img' style='background-image: url(http://media.somesite.com.au/img-101x76.jpg);'></div>

</div>";

        var doc = new HtmlDocument();

        doc.LoadHtml(html);

        var div = doc.DocumentNode.SelectSingleNode("//div[contains(@class,'searched-img')]");

        var url = Regex.Match(div.GetAttributeValue("style", ""), @"(?<=url\()(.*)(?=\))").Groups[1].Value;

        Console.WriteLine(url);

    }

}