In section background picture are cutted

Hi there,

Background images are Not responsive by nature, it's not a theme thing.

What you can do is to use specific images when mobile breakpoint kicks in.

For example, the first image in the page you linked:

@media (max-width: 768px) {
    #generate-section-1.generate-sections-container {
        background-image: url(https://MOBILE-IMAGE-URL-HERE);
    }
}

Adding CSS: https://docs.generatepress.com/article/adding-css/

Can i place photos to a other way in the section?

Not sure what you mean by that?

You can reposition in mobile like this:

@media (max-width: 768px) {
    #generate-section-1.generate-sections-container {
        background-position: center center;
    }
}

Is it possible to insert pictures in section without background?

Yup you will just add it as static image by clicking Add Media.