// ==UserScript==
// @name           AnarchyNetwork Image Replacer
// @namespace      http://www.anarchynetwork.com
// @description    Replaces the top image with one of your choosing
// @include        http://www.anarchynetwork.com/forums/*
// ==/UserScript==

var newImage = "http://img43.imageshack.us/img43/6823/antest.png";

document.body.innerHTML = document.body.innerHTML.replace(/images\/ambient_lighting_blue\/misc\/images\/logo\.png/g, newImage);