A better way would be to go to your MTW main folder then campmap/startpos

open EARLY_XL.txt and add the following text to the bottom:

Code:
//========================================
//
// Override function for the portraits..
//
// When this is specified the game will 
// ignore the factions culture when 
// locating the portrait images and
// use this folder instead..
//
//========================================

PortraitsOverride:: FN_IRISH	"vikings"