At the moment you decided to use rank images instead of text, that's why you see image, and not text. When you go to
Administration control panel (ACP) ► Users & Groups ► Rank administration , you can find ranks you added. For example, I have rank member like this:
![Guest rank title Screen31](https://i.servimg.com/u/f58/20/45/92/79/screen31.jpg)
As you can see, it is a rank that is set if the user has minimum 1 post. Rank title is member and it's visible to the page.
![Guest rank title Screen32](https://i.servimg.com/u/f58/20/45/92/79/screen32.jpg)
All of this is by default. Did you change anything in templates when it comes to rank?