Copy the Unit_ ...png files into your RUS\Graphics\Units\Leaders Units folder.

Copy the Army_...png files into your RUS\Graphics\Armies&Fleets\Leaders Armies folder.

 Copy the mdl files into your RUS\GameData\Models folder.

 Delete the "Models.Cached" file in the same folder. Don't worry, the file will be recreated automatically with the updated information the next time RoP is launched.
(A back up folder of the original model files is included in case you need to revert to the generic portraits.)
