Just go into your saved game's news\html\images\team_logos and league_logos folders and delete everything that doesn't have default in the name (make a backup first just in case) . Restart ootp and it'll rebuild all of them using your new logos.
The reason you have to do this is because when you add logos after you created your game..ootp doesn't look for them and dosen't replace the old logos in the saved game's folders. So deleting them forces ootp to look to the main logos folders to rebuild them.
