Vignetting refers to the gradual darkening of the corners or edges of an image compared to the center. It can occur naturally due to the limitations of a lens or may be purposely added for creative effect. Vignetting can draw the viewer's attention towards the center of the image, creating a visually appealing focus. Photographers may use vignetting to enhance mood, create a vintage feel, or direct the viewer's gaze. Post-processing software can also be used to add or remove vignetting effects. Overall, understanding vignetting is important in photography, as it can impact the composition and overall aesthetic of an image.