How about a thread where we post our custom portraits?
I made two which I currently use. One for heavy armored characters, the other for light armored, leather/overcoat guys:
Drop the large and small versions both into the C:\Users\[Name]\Documents\My Games\Underrail\CustomPortraits folder.
Edit: Backgrounds are set as transparent now so they should interact properly with the ambient of the area (thanks epeli):