Sorry, but it's only apple to oranges if you already know the answer. That answer, explained in the next section, is very clearly intended for someone who didn't already know it:

> This concept of throwing away bits you don't need to save space is called lossy compression. H.264 is a lossy codec - it throws away less important bits and only keeps the important bits.

> PNG is a lossless codec. It means that nothing is thrown away. Bit for bit, the original source image can be recovered from a PNG encoded image.