Hello.As far as I know, for the moment WebSite X5 is not able to compress so well.I tried to use FileOptimizer64before adding images to the program. But in some cases, WebSite X5 converted images and they became larger. Although I did not set any settings to change them.

I tried to optimize images after uploading the site to the Internet, but during the next update, some of the images can be replaced.

Aleksej H. 

Thank you for your quick answer. But unfortunately he didn't answer the question!

There is a program that knows this but only from the paracs line.

You can integrate the program into the "website x5" program?

pingo, a fast image optimizer

pingo is an experimental, fast Web PNG/JPG optimizer which offer lossless, web lossless or lossycompression. it performs image reductions over iterations thanks to recursive multi-processing and multithreading systems

https://css-ig.net/pingo.php

"Does the built-in image resizing tool know this tightness?" - no.

"You can integrate the program into the "website x5" program?" - no. Pingo also can not be integrated with WebSite X5.

HiElisa B., Aleksej H.

I apologize for the misunderstanding. I'm not integrating. But the website x5 program developer team would build on the program. As a future opportunity.