For this use-case, you want to create a new plugin, that stands just next to mine. That means:
- Create a new file in your game/js/plugins and call it, e.g., "CustomMenuPortraits.js" (the name doesn't matter as long as it's ending on "js")
- Paste the code from my last reply
- Yes exactly, you need to adjust the names, and also the numbers inside the $dataArmor brackets.
- If none of your "rules" apply, then my plugin's original functionality comes into play (i.e. the notetag <menu portrait: file> is used)
- In RPG Maker -> Plugin Manager, include your new custom plugin and put it below the menu customizer
This is just a sample code that I offered to you. Notetags just aren't flexible enough; if I were to make a feature that chooses a different picture just for equip, then the next person would request it just for weapons, or states, or any other situation. However, custom code provides you with much more freedom.