A free and simple customisable image gallery that should work on any Shopify themes, including Dawn. This was originally developed by Marcos Wantabe, and Instructions can be found here: https://marcoswatanabe.com/shopify-guides/image-gallery-shopify-dawn
In my version I made some edits to get this working with a few options within my template, including removing margins, adjustable image height ratios, and an option to add a border radius around the images. I also fixed the full width option on desktop so this can be adjusted to display across the shole width of your page on desktop.
It's super easy to add to your theme. Simple copy the file, open your code editor and create and new section file called image-gallery.liquid.
Once added, you will be able to use your visual theme editor to craft a image gallery for your store.