Picture crops while keeping height 100%. How do I do it?

Hello guys,
I need help to realize this picture scaling just like in this website:

https://www.one-works.com/ (site is from one of the major architecture firm in europe and im not related to it in anyway)

If you zoom in and out u can see that the pictures in the homepage « crop » themselves while keeping the height 100%. I really like this way of showcasing your project and i would like to implement it on my website but right now i can't really achieve that result.

Problem lies in the « cropping » of the picture as the zoom goes out.

Do you have any idea on how to achieve this kind of result?

Thank you all