Where does “diimaginasikan” come from?

diimaginasikan (Malay) comes from Malay -kan, from Proto-Malayic *-kən.

Ancestry of “diimaginasikan”, step by step

Step	Language	Word	Meaning
1	Malay	-kan	Used to indicate transitive imperative verbs;...
2	Proto-Malayic	*-kən	—