I made some dwarven portraits when playing, mostly based on the dwarf militia and miners.
The portraits are in a series of 50 pictures, repeating itself four times as the game seems to expect 200 files in the portraits folders. Don't know if that's hardcoded. I have made 45 portraits and threw in my favourites one more time last to fill it out.
Install by unpacking and pasting the content (the tga files) into the mods
...data\ui\greek\portraits\portraits\young\generals
and
...data\ui\greek\portraits\portraits\old\generals
if you for example want to use them for young and old dwarf generals. It is save game compatible and will not interfere with other mods except for the change of portraits.