Eli5: How do zip files work? How do they make files just smaller?

Question

Eli5: How do zip files work? How do they make files just smaller?

In: Technology

Answer 1

I have a bag of 15 marbles. There are several ways I could tell you what colors the marbles are, but here are 2 major ways.

The first: 5 blue marbles, 3 red marbles, 2 yellow marbles, green marble, 4 purple marbles.

This is an unzipped file.

The second I will show you is this:

Same information, but shorter, if you know how to read it.

5b,3r,2y,g,4p

This is a zip file. Unlike the first, it doesn’t mean anything unless you know the symbols used, but it’s easy to convert it back to English if you do.

Anyway, the actual method will vary a bit, but file compression such as zips use similar methods to take the same information and smash it down to be smaller, then make it bigger again when needed.