* https://developer.mozilla.org/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images * https://cloudinary.com/blog/responsive_images_with_srcset_sizes_and_cloudinary * https://www.html5rocks.com/en/tutorials/responsive/picture-element/ * https://alligator.io/html/picture-element/ * https://www.smashingmagazine.com/2014/05/responsive-images-done-right-guide-picture-srcset/
