Get All Images From External URL / Website - asp.net

Question

This code is working nice... I dont have problem.
var urls = from lnks in document.DocumentNode.Descendants()
where (lnks.Name == "a" && lnks.Attributes["href"] != null &&
(lnks.Attributes["href"].Value.ToString().Contains("jpg")
|| lnks.Attributes["href"].Value.ToString().Contains("png")
|| lnks.Attributes["href"].Value.ToString().Contains("bmp")
|| lnks.Attributes["href"].Value.ToString().Contains("jpeg")
|| lnks.Attributes["href"].Value.ToString().Contains("gif"))
)
select new
{
Url = lnks.Attributes["href"].Value
};
But This one always return null:
var urls = from lnks in document.DocumentNode.Descendants()
where (lnks.Name == "a" || lnks.Name == "img") &&
(lnks.Attributes["href"] != null || lnks.Attributes["src"] != null) &&
(
lnks.Attributes["href"].Value.ToString().Contains("jpg")
|| lnks.Attributes["href"].Value.ToString().Contains("png")
|| lnks.Attributes["href"].Value.ToString().Contains("bmp")
|| lnks.Attributes["href"].Value.ToString().Contains("jpeg")
|| lnks.Attributes["href"].Value.ToString().Contains("gif")
|| lnks.Attributes["src"].Value.ToString().Contains("jpg")
|| lnks.Attributes["src"].Value.ToString().Contains("png")
|| lnks.Attributes["src"].Value.ToString().Contains("bmp")
|| lnks.Attributes["src"].Value.ToString().Contains("jpeg")
|| lnks.Attributes["src"].Value.ToString().Contains("gif")
)
select new
{
Url = lnks.Attributes["src"] != null ? lnks.Attributes["src"].Value : lnks.Attributes["href"].Value
};
What's my mistake ? and is this a correct way to take images ?

Answer 1

This is the code for image nodes. Make a function out of it and you can use it for any node:
GetLinksFromDocument(document, nodeName, linkAttributeName)
using HtmlAgilityPack;
var urls = new List<string>();
var prefixList = new[] { "jpg", "jpeg", "png", "bmp", "gif" };
var document = new HtmlWeb().Load("http://jwillmer.de");
var imageNodes = document.DocumentNode.Descendants("img");
var imageLinks = imageNodes.Where(node => node.Attributes.Contains("src"))
.Select(node => node.Attributes["src"].Value);
urls.AddRange(imageLinks.Where(link => prefixList.Any(link.EndsWith)));