How to create a stacked grid gallery in Brine (similar to York template) OR add parallax to full size image blocks in an index?

Site URL: https://mango-harmonica-5r95.squarespace.com/new-gallery-1

Hi! 

I recently transitioned over from the York family template to the Brine template. 

I am trying to create a stacked grid gallery with 1 image per row with a parallax effect. This is the exact look I'm trying to recreate (from the York template - original website): https://www.nicolemok.me/grants-gov 

On my current website, it is in a slideshow format: https://mango-harmonica-5r95.squarespace.com/new-gallery-1

I tried another method where I managed to at least make each image into a full size image block on separate pages under an index so it looks similar to what I have before. But I can't seem to pull the code for the parallax effect into what I'm doing now in the Brine template. Here's what I'm talking about: https://mango-harmonica-5r95.squarespace.com/grants-gov2 

So basically, I need help with either --> adding the parallax effect to each full size image block (/grants-gov-2) OR changing the slideshow format (/new-gallery-1) to a stacked grid with 1 image per row with the parallax effect. Ultimately, I just want it to look like my original website from the York template. 

Appreciate the help! THANK YOU!