Prestige Theme: How do I make all of my photos a 3:4 (portrait) ratio?

Store Design
1

Hi, I would like to make it so all of my photos are the same size with a 3:4 ratio. The theme offers other sizes, but not the one I’m looking for.

Thank you.

2

This will involve a little bit of coding to get that 3:4 ratio you’re looking for. By any chance, do you have any experience coding in Shopify?