I'm not sure how to go about doing this.

I want it so that when someone enters the following text :b: into the description of their link, it should change it to an image that I have stored on my server

In a modern day forum, I would simply use :b: as a censored word and translate the censored word to the <img src= bla bla bla.gif> html code.

Is there maybe a simple way of doing that, maybe as a template golbal or something like that?

So that when somone types :b: it gets translated onto the detailed.html page as the img src html code tag of my choice.

Thanks,

P.S. I thought it might be as simple as adding a template global named :b: and the contents of the global be the actual html img src tag, but that didn't do anything for me.