Pixel Shaders are small programs used in computer graphics to determine the color and brightness of individual pixels on the screen. They run on the Graphics Processing Unit (GPU) and allow for complex visual effects, such as lighting, shadows, and textures, enhancing the realism of images in video games and applications. These shaders work by processing data for each pixel, taking into account various factors like light sources and surface properties. By manipulating these elements, Pixel Shaders can create stunning visuals, making them essential for modern graphics rendering in both real-time applications and pre-rendered scenes.