Images are not reducing in size equally (responsive - expand and contracting)

Hi there,

I have 4 images that make 1 image… and when they expand and contract in responsive modes they do not change equally… please help!

Image beside About Us.
https://preview.webflow.com/preview/dmc-projects?utm_medium=preview_link&utm_source=designer&utm_content=dmc-projects&preview=324f3261c6ca42ea55255b93dab3b037&mode=preview


Here is my site Read-Only: LINK
(how to share your site Read-Only link)