>but how in the heck is a gallery lightbox anywhere near 4 lines of CSS and two lines of PHP?
Most implementations are massively bloated as a legacy from the jQuery days when that was neccessary. CSS is incredibly powerful now, and the browsers are all evergreen, so it's pretty trivial to implement a pure CSS/HTML gallery:
This is fully featured, with indexing, scrolling, animation, etc., but you could slim that down even further to just a few lines for a simple automated slider. Obviously doesn't work if you need managed control, but 99% of gallery use-cases are just flipping through a homepage hero like the OP.
Most implementations are massively bloated as a legacy from the jQuery days when that was neccessary. CSS is incredibly powerful now, and the browsers are all evergreen, so it's pretty trivial to implement a pure CSS/HTML gallery:
https://css-tricks.com/css-only-carousel/
This is fully featured, with indexing, scrolling, animation, etc., but you could slim that down even further to just a few lines for a simple automated slider. Obviously doesn't work if you need managed control, but 99% of gallery use-cases are just flipping through a homepage hero like the OP.