Select the small one for the small portrait. Select the medium or large one for the large portrait.
RACE = HU (Human) or DW (Dwarf) or HE (Half Elf) etc *They will simply show up in the custom section, they are named like You should now be able to use the custom portraits with no issue. Copy these image files into the new 'portraits' folder you created Open the override folder in the zip file
Open the zip file you downloaded (ie the Portrait Pack) Create a new folder and name it 'portraits' Look for a 'Baldur's Gate - Enhanced Edition' or 'Baldur's Gate II - Enhanced Edition' folder