坚持自定义验证码主题要求

Question

所以我正在设定一个自定义验证码，我当然希望遵守这些要求，

While theming does give you many options, you need to follow some user interface     consistency rules:

You must state that you are using reCAPTCHA near the CAPTCHA widget.
You must provide a visible button that calls the reload function.
You must provide a way for visually impaired users to access an audio CAPTCHA.
You must provide alt text for any images that you use as buttons in the reCAPTCHA widget.

src: https://developers.google.com/recaptcha/docs/customization

前三个并不难，但第四个有点棘手 - 我没有使用实际图像，但是我使用的是fontello glyphs。我理解替代文字是为了防止图片无法加载，但它是否也是通过视觉障碍者的文本到语音应用程序读取的内容？如果是这样，那么在这些字形上设置alt文本也是个好主意吗？

谢谢你， 悉尼