def extract_sub_attributes(browser):
    """
    Extract sub attribute tags of avatar image from web page

    :param browser: opened browser
    :type browser: webdriver.Chrome
    :return: sub attribute tags of avatar image
    :rtype: list
    """
    sub_attrs = browser.find_elements_by_class_name('sub-attr')
    sub_attr_results = []
    for sub_attr in sub_attrs:
        sub_attr_results.append(sub_attr.text)
    return sub_attr_results