Help me identify something (photoblog)

I’m trying to figure out how the navigation works on sites like this https://www.huddletogether.com/gallery/japan/

I’ve seen the photo nav like that on other sites as well, but can’t figure out if it’s a script or plugin or if they did it by hand. Does anyone know if there is a WordPress plugin/addon that does something like this? If WordPress doesn’t, do you know what does?