Guns
Throughout the film, guns are a silent threat, emerging from inner coat pockets out of nowhere, wielded willy-nilly by anxious and unreliable villains. Miles is seen being shot and killed in the early parts of the film, but we only see the pistol from the shooter's point of view. From these early moments of the film, the gun as an image establishes that Sam is embarking on a dangerous mission with high stakes. Additionally, Cairo wields his gun twice, coercing Sam into letting him search his office, and Wilmer is always holding a gun or two, threatening to kill Sam. Curiously enough, while Sam is an expert at disarming an armed enemy, he insists that he does not own a gun himself.
Fire
Gutman finds out that the Maltese Falcon is on a ship arriving in San Francisco from Asia. He sends his men to retrieve the Falcon and in the process they accidentally burn down the ship. The image of the giant ship burning shows the lack of care with which Gutman and his accomplices go about their business, their lack of regard for anything but their own aims. The image of a burning ship is an image of destruction, an extension of the destruction that Gutman has imposed on the world in his search.
Curtains
The curtains in Sam's apartment—which he refers to, in typical noir style, as a "dump"—are almost always evocatively blowing in the wind. When Sam first gets the call that Miles has been shot, we see his curtains blowing in a breeze, but we cannot see Miles. The curtains rustle in the breeze, suggesting the threat of an intruder, an image of outside forces coming inside. Then later, when he leans down to kiss Brigid as she bemoans her life of lies and crime on his couch, Sam is distracted before he makes it to her lips by the sight of Wilmer standing on the streetcorner watching them. The camera pans away from Brigid's face, up to the open window, and the viewer sees Wilmer through the curtains, which are still blowing in the breeze.
Out of the Shadows
Similar to the image of the open window, shadows are a prevalent image throughout the film, emblematic of its status as the quintessential noir. Shadows and the mysterious unseen are common images in noir, symbols of the circuitous mysteries taking place. When Sam is looking for Brigid, he finds her waiting for him in the shadows near his apartment where she's been hiding. Brigid is both literally and figuratively "in the dark," in need of protection and shelter. Furthermore, her being in the shadows reflects the more shadowier parts of Brigid's personality; she cannot quite be trusted. In film noir, almost no one can be trusted. The shadows that abound reflect the untrustworthy and the unseen.
