Image Blocks displayed differently on mobile and desktop

Hey everyone, I'm trying to design my photography website and have been having trouble getting it to look the way I want.

I've spent a great deal of time manually adding image blocks one by one (any way to add multiple image blocks at once by the way?) and adding spacers too to create a photo collage effect on my blog post.

It doesn't translate to my blog posts however, and ends up stacking very linearly above one another. The mobile version doesn't include the spacers and when I tried a custom CSS to add the spacers back, it still has that same vertical stacking effect. It looks so plain and boring. Any help with this? 

I'm on squarespace 7.1 by the way.

Yeah I have the same issue 

You can edit page > Click Mobile icon on top right > Then design layout on mobile.

See this detail: https://support.squarespace.com/hc/en-us/articles/6421525446541-Editing-your-site-with-Fluid-Engine