The pattern of blood that Caleb wipes on his T-shirt immediately after killing his brother's girlfriend is different than the pattern shown when he enters his house.
When Betty Applewhite is shown a photograph of her son's girlfriend's body, the body is partially covered with a jacket, covering the victim's left arm and only exposing a few fingers on that hand. Her son Matthew is later shown committing the murder (in a flashback), and his jacket is laid over the body with the majority of the victim's left arm shown - much more than just the few fingers shown in the original photo.
When Bree goes to hand the frog ornament back to her new neighbor, Mary Alice, the frog is pointing away from Bree. When the camera angle changes, the front is pointing towards her.