function mapImageResources(rootDir, subDir, type, resourceName) {
    var pathMap = {};
    shell.ls(path.join(rootDir, subDir, type + '-*'))
    .forEach(function (drawableFolder) {
        var imagePath = path.join(subDir, path.basename(drawableFolder), resourceName);
        pathMap[imagePath] = null;
    });
    return pathMap;
}