Doesn't encapsulation increase uploaded/downloaded the file size?

I don't know if I should've asked this question on askprogramming but this sub seemed more relevant. I've read the rules. This question seemed appropriate.

I've been wondering this for years and I really don't get it. I couldn't find an answer yet.

We have a file. We're going to send it using the internet. The file gets divided. Those divisions gets encapsulated with several headers and it gets sent division by division. The encapsulation diagram shows that the actual size of the file division in the whole encapsulation is very small. Headers occupy most of the space.

When I look at the actual transmission, what we have sent is exactly the file's actual size. When we get the file, what we received is also the file's size.

What happened to all the data? Why do we transmit only the file? What happened to the headers? Did we not transmit or receive those?

This gets me really confused.