If you're using Turbo 2.0 +, please see the following article
In the latest version of all of our themes, we've added in a "page.gallery.liquid" file to make creating a gallery page a little easier. All you have to do to use this new page layout is create a page and upload your images, and we'll walk through those steps below.
A new page can be created by going to Sales Channels > Online Store > Pages > Add new page in the Shopify admin area. In that new page, you can upload all the images you'd like to use, with no need to do any formatting/spacing, that will all be taken care of!
If you'd like to have regular text content on your page, it can be added in below the images. After you've typed/pasted in your text, if you click the '<>' icon to flip to the HTML view of the page, right before your text starts a 'split' can be added in (you may be familiar with this from the product template), it would look like this:
<!-- split -->