The zip contains two portraits for each of the NWN2 Official Campaign companions: Amie, Ammon, Bevil, Bishop, Casavir, Construct, Elanee, Grobnar, Khelgar, Kipp, Neeshka, Qara, Sand, Shandra, and Zhjaeve. [Click here to download]
For installation, unzip the .tga files into your NWN2 > Portraits folder. To use, double-click the character portrait in the Character window from in-game and select for each applicable companion.

Portraits all came from here.