import java.io.File;
import org.jsoup.Jsoup;
import org.jsoup.parser.Parser;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Node;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.TextNode;
import org.jsoup.select.Elements;


public class grabImages {
                File input = new File("...HTML");
                Document doc = Jsoup.parse(input, "UTF-8", "file:///C:...HTML");

                Elements img = doc.getElementsByTag("img");
                Elements alttext = doc.getElementsByAttribute("alt");

                 for (Element el : img){
                     if(el.attr("img").contains("alt")){
                         System.out.println("is the alt text relevant to the image? ");
                         }

                         else { System.out.println("no alt text found on image");
                         }
                    }

}

el.attr("img")

public class Controller {

        public static void main(String[] args) throws IOException {

            // Connect to website. This can be replaced with your file loading implementation
            Document doc = Jsoup.connect("http://www.google.co.uk").get();

            // Get all img tags
            Elements img = doc.getElementsByTag("img");

            int counter = 0;

            // Loop through img tags
            for (Element el : img) {
                // If alt is empty or null, add one to counter
                if(el.attr("alt") == null || el.attr("alt").equals("")) {
                    counter++;
                }
                System.out.println("image tag: " + el.attr("src") + " Alt: " + el.attr("alt"));
            }
            System.out.println("Number of unset alt: " + counter);

        }

    }

public class grabImages {
      public static void main(String[] args) {
         Document doc;
     try {
         doc = Jsoup.connect("...HTML").get();
         Elements img = doc.getElementsByTag("img");

          for (Element el : img){
                                if(el.hasAttr("alt")){
                                    System.out.println("is the alt text relevant to the image? ");
                                }
                                else {
                                    System.out.println("no alt text found on image");
                                }
                               }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
               }
}

Document doc = Jsoup.connect(url).get();

    for (Element img : doc.select("img:not([alt])"))
        System.out.println("img does not have alt: " + img);