At some point around season 7 of Family Guy I thought to sense a change in the animation style (IMHO for the better), especially of Peter Griffin. Before that the characters used to look kind of melancholy, with sad eyes, but now Peter's eyes are sort of "maddened".
First of all, am I just imagining this or was there really an actual perceivable change in the animation style around this time? If yes, when did this change occur specifically and what were the reasons for it? Was this just due to a different animator or was it a deliberate decision by the makers?