What are the differences between saving an image as a JPEG 100 and a JPEG 20 in terms of quality and file size?

When saving an image as a JPEG 100, the quality is higher and the file size is larger compared to saving it as a JPEG 20. JPEG 100 will have less compression and therefore better image quality, but it will result in a larger file size. On the other hand, JPEG 20 will have more compression, leading to lower image quality but a smaller file size.