Listar imagens da classe
by Ivan Ferrer
HTML
<div id="opa"></div>
JavaScript
var css = 'background-image: url(1.png), url(2.png), url(3.png), url("4.png")'
var regex = /[^background\-image\:\s,\"\'\(\)]+[^url(.+)]+[^\"\')]/gi;
var arr = css.match(regex);
document.getElementById('opa').innerHTML = arr.join("<br>");