The graphics are stored in the file, along with any other theme changes you made.
FMP 12 may not be able to display these, it sounds like this is the case. Features unique to 13 will not be available in 12 clients, and you might want to require 13 if you develop with them. There's enough different with 13 that you really need to decide where you set the bar and stick with it.
I'll do that. Thanks, Mike.