Script to automate responsive images

Hello,

I'm looking for a script that will allow me to automatically get responsive images.

Let me explain: on the home page of my website https://www.p3x.fr, we find images in the content with a defined size.
When reducing the size of the screen, the css reduces the size of the images with an automatic height and a width of 100%.

The problem is that it is not optimized.
To optimize these images, I would have to create different formats.

Is there a technique to avoid this?

Thank you