Yeah, to add a new portrait you basically have to:
* Add a new icon to portraits.dds & resave the file
What u mean by resave? Reimport in editro and save?
Open with an image editor tool (convert from DDS to something else if necessary), add the portrait, save in some lossless format (PNG is ok), convert to DDS using NVDXT or something similar.
I undetstand, but how to set game use that dds file, not those which located in .pak file?
Just put it in right folder in main directory?