I found, on the character files, the address where the information about the portraits is. This means I have been able to change the portrait of an already created character. This doesn't change the portrait on the "add to party" menu, which leads me to believe that those are saved somewhere else. Will have to check. I'm also sure that changing the portraits on the save files won't be much harder. Unfortunately, I do not have the know-how to make an interface program (pretty much like the portrait wizard) to make these changes... I was wondering if someone would be willing to give me a hand on that department?
UPDATE: Found where the portrait information is for the "add character" menu. Now on to the savegames... Errrr... please someone let me know if I'm doing something that has already been found, so I can stop making a fool of myself
