using APNSoft.WebControls;
using System.Text.RegularExpressions;

APNSoftInclude APNSoftInclude1 = new APNSoftInclude();

APNSoftInclude1.IncludeFileURL = "http://www.yahoo.com/";
APNSoftInclude1.RequestURLTimeout = 10000;

string _Result = APNSoftInclude1.Render();
string ImgsFromSrc = "";

if(Regex.IsMatch(_Result, "<img[^>]*>"))
{
  ImgsFromSrc +=
    Regex.Matches(_Result, "<img[^>]*>")[1].ToString();
  ImgsFromSrc +=
    Regex.Matches(_Result, "<img[^>]*>")[3].ToString();
  ImgsFromSrc +=
    Regex.Matches(_Result, "<img[^>]*>")[4].ToString();
}

Response.Write(ImgsFromSrc);