ELI5: Explain Like I'm 5

Gaussian pyramid

Gaussian pyramid is a way to make an image look smaller, while still keeping all the important parts. It works by taking an image and splitting it into 6 or more layers. Each layer is smaller than the previous one as it has fewer details. This way, you can take a big picture and make it fit onto a smaller screen. It also makes the image look smoother and less pixelated.