Cage

cage.js

// ==UserScript==
// @name         New Userscript
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        *://*/*
// @grant        none
// @require      https://code.jquery.com/jquery-3.4.1.slim.min.js
// ==/UserScript==

(function() {
    'use strict';
jQuery(document).ready(() => {
    var rand = () => { return (Math.floor(Math.random() * 500)) + 100};
    var url = (el) => { return "https://www.placecage.com/c/" + el.width + "/" + el.height;}
    setInterval(() => {jQuery('img').each((idx, el) => {jQuery(el).attr("src", url(el))})}, 2000);
});
})();