Burning Money
Towards the end of the film, the Joker sets a large stack of money on fire in a warehouse. The image signifies the irreverence that he feels towards money and societal norms and separates him from the common criminal. He is not simply a man looking to score some extra cash, but someone who is much more unpredictable and demented, someone who wants to create chaos for its own sake.
The Joker Himself
The Joker is introduced as he interrupts a meeting between the mob bosses. Nolan films the Joker from behind him so we only see the rear of his body as all the bosses look towards him. When we finally do see him, he is wearing his characteristically messy and unsettling clown makeup, and his hair is dirty and matted. He is the image of a villain who is completely unhinged and unconcerned with the trappings of regular human beings.
Two-Face
After falling onto the floor in the warehouse and having half of his face burned off, Harvey Dent is deformed and scary looking. Half of his face is the wholesome and handsome face of Gotham's DA, while the other is skeletal, bloody, and grotesque. His ruined face is part of what leads to his transformation into the heartless killer Two-Face.
The Dark Knight
The end of the film shows Batman speeding away on his motorcycle, running from the cops after taking the blame for Harvey Dent's murders as Two-Face. It is the image of a misunderstood hero, whom the public now views as a killer, running from the normal life that he covets in order to do what is right.
