On a chest x-ray, pneumonia appears as an area of increased opacity or whiteness, indicating lung consolidation where air is replaced by fluid or pus. Here are some examples.
Right Middle Lobe Consolidation
Right Lower Lobe Pneumonia, Anterior Segment
Right Lower Lobe Pneumonia, Superior Segment
Left Lower Lobe Pneumonia, Anterior Segment
Left Lower Lobe Pneumonia, Posterior Segment