hobbit_longon

Who said anything about encryption?

The OP is demonstrably an idiot. He calls himself "Developer, CEO of The Student Cloud", and yet he apparently has no clue whatsoever about the most basic compression algorithms. Zipping compressed images is something that my mother does.

I'm not misunderstanding anything. Your very last point contains:

"We still don’t quite understand why nobody sends gzip’ed images"

gzipping web content isn't optimisation 101, that's optimisation 102.

Optimisation 101 is profiling.

Is this a joke?

You want to know why people don't gzip their images? What benefit do you think you get from gziping a jpeg or png stream? Why were you trying it in the first place?