Do you want portraits to change if an unit is promoted, or specifically on some points in the story? This makes it work on ANYTHING that uses portraits, even in supports and conversations! No extra eventing or conditionals needed.
Dynamic portraits is simple, it has a table where you input details of the base portrait you want to check, what new portrait to replace it for, and the conditions for said replacement. Portrait changes can be done by Event Flags, by characters existing, by characters being of a certain class, and any combination of these.
If you need reference to understand how it works, just look at the comments in the event file:
Thanks to @Retina for commissioning this and allowing it to become free to use.