Based off the exact HTML you provided, you can extract the image urls by calling the attr(String key)
method and passing in src
(see docs). Example:
String html = "<ul class='myClass'><li><a><img src='myImageSrc1.png'/></a></li><li><a><img src='myImageSrc2.png'/></a></li></ul>";
Document doc = Jsoup.parse(html);
Elements castsImageUrl = doc.select("ul.myClass > li > a > img");
for (Element el : castsImageUrl) System.out.println(el.attr("src"));
Which outputs:
11-06 09:45:11.313: I/System.out(454): myImageSrc1.png
11-06 09:45:11.313: I/System.out(454): myImageSrc2.png