Thank you for pointing this out (reading on a desktop, so I'm wouldn't have noti...

Thank you for pointing this out (reading on a desktop, so I'm wouldn't have noticed otherwise). The source does this via:

    <figure
     class="book-fullbleed ipad-portrait-img">
       <img src="ima( … )9.jpg" alt="">
    </figure>
    <figure
     class="book-fullbleed ipad-landscape-img">
      <img src="imag( … )x1039.jpg" alt="">
    </figure>

And where ipad-landscape-img is backed by media-selectors in bookstrap.js.

I wonder if this "bookstrap" think is related to bookstrap.org? The site is blank, and the github-repo linked to from https://www.npmjs.com/package/bookstrap is gone/empty …

Either way it's refreshing to see some people still make sensible design without a ton of minimized CSS (even if this still pulls in two big stylesheets and a js-file … all to display some text … ).