How to Create An Responsive Custom Landing Page

hey guys i wanted to create an responsive custom landing page that shows image based on the device size example telugu360.com when you open that website you can get an landing page of image that fits the screen and changes based on device size can some one help me out how to set up that
thanks in advance

Simple use Bootstrap.

Check the Bootstrap tutorial on this link https://getbootstrap.com/

All modern theme uses srcset to display appropriate image size as per device screen width.

You can use JetPack Photon. It automatically add scaled image size.