Anyone know how to add pictures, spacers and titles to Rig parameters

When they appear in final cut pro? 
Like the attached. Anything would be preferable to nothing. 

If you sign up with FxFactory, you can gain access to their API for adding these kinds of features to template parameters.
fxfactory.com/developer/adding-custom-ui/

I believe* you will be limited to producing your templates through their UI with FCP and you will have to deal with your templates breaking every so often as software updates to FCP and the OS tend to require updates to the FxCore as well. [*I have no personal experience with the FxFactory "system" — I opted to never to have anything to do with them.]

If all you need are section dividers (text only - no images), then you can pull that off in Motion itself without any external UI code.

Up til now, 100% Motion made templates have never broken* in Final Cut. [I had one break, but it was a custom 3D Model made from a custom font that probably wasn't designed well enough to begin with.]