If you are talking about what I think you are talking about, upload it as a shield or guild image and use <img src=shieldcode.png height=100 width=100> or <img src=profilelogo_guild%032logo.jpeg height=100 width=100>
put %032 where spaces in the guild name are. (I'm not entirely sure if that is correct, someone please confirm or deny it.) You can also change the 100 to any number you want within reason to make it bigger or smaller