Flexbox Wrap not wrapping correctly

Hi guys,

I’ve designed my portfolio using CMS collections, and I have a collection list with flexbox and a wrap that should be displaying either 2 small pictures in a row or 1 big like on this preview:
https://preview.webflow.com/preview/first-lights-design?utm_medium=preview_link&utm_source=designer&utm_content=first-lights-design&preview=e9bbc11dd45e2c79f45bd7aa08ba9929&pageId=60e223a39d6c02e8468f6a81&itemId=60e223a39d6c02371b8f6ad0&workflow=preview

Only problem is that when I publish, the small images are scaled up and fill the width, even though layout looks goo on preview.

Any help with this would be much appreciated.
Thanks,

A.J