How to compress images under PageSpeed ​​Insights?

Question

Google

Tell me how to optimize images for PageSpeed ​​Insights without losing quality?

I'm currently compressing with gulp-imagemin and imagemin-mozjpg. But no matter how I optimize the pictures, the test still gives information that you can compress more. If you compress less than 70%, then the output quality is poor.

Answer 1

Overtake in webp, in my opinion then does not require compression.

Answer 2

you need to take a different approach to the
JPEG test, of course, everything that is less than 70% is noticeably different for the worse: going in this direction is a dead end