This is an image of my cats. The mood that is conveyed is relaxation/sleep. This wouldn't reinforced through lighting if the subjects were human, but because of them being cats, the lighting helps by forcing their heads deeper into their bodies to keep the lighting out. There are several sources here, so I will map all of them.

This is from a Pearl Jam concert. The mood is contemplative or somber. This is conveyed through the lighting by the color and the angles.

This source is the strongest and, to me, is the key to creating the mood.

The image is of a microphone and the mood conveyed is strength. This is accomplished through the angle of the camera and through the angle of the spotlight.

This image is of a couple looking serious. Notice the mood in the previous sentence? This is coneyed not only through the looks of the people, but also through the lighting coming from behind the people.

This image is titled "Dangers of Smoking." The mood is scary or dangerous. Remember using the flashlight to shine a beam of light up under your chin to add weird shadows on your face? Yeah, that's whats going on here.