Requirements: PHP

1. Put your images in the img folder
2. Open http://example.com/photosheet.php in your browser
3. Save as index.html or else

Or from the command-line:

php photosheet.php > index.html

Details

• Images should be a reasonable size and compressed beforehand, as no thumbnails are generated
• figure.landscape and figure.portrait are available for styling
• Navigate within the lightbox on tap/click, swipe/scroll, on focus with Tab, or with the ← → keys

Default variables in photosheet.php:

$site_title = "Photographs of Roadside America";
$site_desc = "by John Margolies";
$site_style = "style.css";
$img_folder = "img/john-margolies";
$allowed_types = ["gif","jpg","jpeg","png","webp"];

Default variables in style.css:

--textsize: 16px;
--textcolor: #eee;
--backcolor: #0e0e0f;
--margin: calc(0.8em + 1vw);
--thumbsize: 156px;
--slide-transition: auto;

Please check v0.1 for a simpler javascript-free version.
The CSS images slideshow alone is available here.