A frame buffer is a portion of memory used to store pixel data for images displayed on a screen. It holds the color and intensity information for each pixel, allowing the computer to render graphics smoothly. When a new image is generated, the frame buffer is updated with the new pixel data before being sent to the display. In computer graphics, the frame buffer plays a crucial role in rendering images, especially in real-time applications like video games. It enables the efficient management of visual data, ensuring that what you see on the screen is a coherent and up-to-date representation of the graphics being processed by the graphics processing unit (GPU).