I'm new to the game and don't know if you can add to an on going game. I do know you can add them when you create your game. It's the same as loading the real NFL schedule. IE there is a spot or button on that same page where you can navigate to your coach file. The pics just need to be added to the coaches folder here...
C:\Users\xxxx\Documents\Wolverine Studios\DDSPF 2022\Leagues\Rams The Game 2\HTML\Images\Coaches
You will have a some coach's pics not show up in game. Most do but I know I had at least 2 that did not. Those files names did not have the proper form so you need to check them out and fix. IE in the file you'll see 'Kevin_O_Connor' which should be 'Kevin_O'Connor'.
The files can be found in the mod forum here..
https://www.draftdaysports.com/board/viewtopic.php?f=285&t=34102The coaches are from 2020 but that, too me, was better than fictional. Right now there is not a 2021 mod listed in the mod forum.
The pics are here and also the coach file itself. Remember where you put the coach file as you'll have to navigate to it and select it to get it in your game.
Hope that helps.