<?php

$urls = array("http://shop.google.com/pic/android2014-1.jpg",
"http://s...content-available-to-author-only...t.com/pic/buy2.gif",
"http://s...content-available-to-author-only...y.com/pic/android2014-2.jpg",
"http://s...content-available-to-author-only...e.com/pic/android2014-3.jpg",
"http://s...content-available-to-author-only...s.com/pic/android2014-6.jpg",
"http://s...content-available-to-author-only...t.com/pic/android2014-4.jpg");

$domains = array_map(function($url) { return parse_url($url, PHP_URL_HOST); }, $urls); 
var_dump($domains);