Latin word pictus comes from Proto-Indo-European *peyḱ-

Detailed word origin of pictus

Dictionary entry	Language	Definition
*peyḱ-	Proto-Indo-European (ine-pro)
*pi-né-ḱ-ti ~ pi-n-ḱ-énti	Proto-Indo-European (ine-pro)
pingere	Latin (lat)
pictus	Latin (lat)