title: Responsive image lightbox
body: <p>I am trying to create a responsive photogalery. I've solved responsive thumbnails (they load the right image according to screen size and devicePixelRatio). But I also want a responsive lightbox for them. I hope there must be a suitable library...</p>
  
  <p>The main problem is how to load only the correct image size. For example, on my 480*320 mobile phone, it is pointless to load 2Mpx images. However, on a 17" screen, it is basically what I want.</p>
  
  <p>I hope this is simple, but I haven't found a suitable lightbox library. Well, lightboxing a HTML would be a solution, but it seems to be rarely supported. The Magnifier Popup supports it, but it seems to be aimed for some different purposes and I can't make it working for photogallery.</p>