The BBCode plugin seems to have a few bugs...... namely when setting the size of an element.
When you attempt to change the size of an element you end up with something like this beinjg inserted at the start: "=18px".
Also, I tried to do something like this:
http://www.condorstudios.com/stuff/Untitled-1.png -- Too large to display, forum cuts it off
But when I went into the "source" window and then came back to the normal editor it looked like this: