A vignette in photo editing is a technique used to draw attention to the center of an image and soften the edges. It gives an image a faded, vintage look and provides a subtle frame for the center of the image. This effect can be used to make a photo look more artistic, or to set the mood. Vignettes can be achieved by adjusting the brightness, contrast, and saturation of the pixels on the edge of the image. When done correctly, a vignette can add depth and texture to a photo, making it more visually intriguing.