Originally Published Nov 28 2017, updated Nov 29 2018
srcset attribute and with and takes best advantage from the progressive JPEG image format.
lazysizes is an easy yet robust JS library used to delay the loading of images (iframes, scripts, etc) until they come into view, as well as loading the appropriate sources according to the breakpoints defined in the markup to fit any screen size. Designed for high performance websites to improve the page load time and to save the bandwidth.
The lazy-image library allows to load image sources on-demand (e.g. click, in view, etc).
Img2 is a web component that lazy-loads and pre-caches images to improve the page loading time.
Also comes with an image blur effect that allows the user to preview the image until the image is completely loaded.