static/ext/src/ux/AceEditor.js
function imageUrl(path) {
    var dataUrl;
    try {
        dataUrl = require('text!cockpit/ui/' + path);
    } catch (e) { }
    if (dataUrl) {
        return dataUrl;
    }

    var filename = module.id.split('/').pop() + '.js';
    var imagePath;

    if (module.uri.substr(-filename.length) !== filename) {
        console.error('Can\'t work out path from module.uri/module.id');
        return path;
    }

    if (module.uri) {
        var end = module.uri.length - filename.length - 1;
        return module.uri.substr(0, end) + "/" + path;
    }

    return filename + path;
}
function imageUrl(path) {
    var dataUrl;
    try {
        dataUrl = require('text!cockpit/ui/' + path);
    } catch (e) { }
    if (dataUrl) {
        return dataUrl;
    }

    var filename = module.id.split('/').pop() + '.js';
    var imagePath;

    if (module.uri.substr(-filename.length) !== filename) {
        console.error('Can\'t work out path from module.uri/module.id');
        return path;
    }

    if (module.uri) {
        var end = module.uri.length - filename.length - 1;
        return module.uri.substr(0, end) + "/" + path;
    }

    return filename + path;
}
Work out the path for images.
TODO: This should probably live in some utility area somewhere