I finally got to try that out, and it works great eg. However, I want to go another step, but I haven't been able to figure it out on my own. I'd like to have it a bit recursive so it could convert something like the following:

[link=somepage.html][img]someimage.jpg[/img][/link]

The way that it is right now, that line would just have the img tag converted, but not the link.

I seek further wisdom.