When Peter is telling Chris that he just comes from a line of husky Griffins, Lois is barefoot, but when she tells Chris that she will put him on a diet and Peter will help him exercise, she is wearing her magenta slippers.
When the hotel manager announces that Chris is "just a fat kid," Lois' lips disappear.
when Lois comes into the bathroom to see Brian gnawing on himself, the light switch appears to be level with the faucet. However, when Chris runs into the bathroom and the camera zooms in to his face, the light switch appears much higher.
When Lois is asking Chris who would consider liposuction, Stewie's face is covered in chocolate. After Peter comes in, it is gone.
When Meg says, "Mom, can I get lipo too?", the neckline on her pink shirt disappears when facing Lois; the neckline reappears when facing Peter.
When Peter is talking to the man from the Beautiful Peoples Club at the grocery store, his glasses appear and disappear multiple times.
In the scene where Brian is having acupuncture you see that there are no needles on his chest but when the camera closes up to the doctor, needles appear in his chest as well.
When Peter is staring at his reflection in the rear view mirror, he is talking but he appears not to be talking.
When Old Yeller is asked if the message is on the machine, the top gun is first present, then disappears, but re-appears when the mother takes it off to kill him.