Justin Downey

This plugin adds the <code>loading</code> attribute to IMG tags found when filtering <code>the_content()</code> to support native image lazy loading.
For more information about lazy loading images using this new native browser image attribute, check out this article: <a href="https://addyosmani.com/blog/lazy-loading/" rel="nofollow ugc">https://addyosmani.com/blog/lazy-loading/</a> and for a little more depth into what we’re doing here, check out our <a href="https://jdmdig.it/30nXp7h" rel="nofollow ugc">explainer post</a>.
Historically, to limit the impact offscreen images have on page load times, developers have needed to use a JavaScript library (like <a href="https://github.com/aFarkas/lazysizes" rel="nofollow ugc">LazySizes</a> or <a href="https://www.andreaverlicchi.eu/lazyload/" rel="nofollow ugc">Vanilla-LazyLoad</a>) in order to defer fetching these images until a user scrolls near them. What if the browser could avoid loading these offscreen images for you?
The <code>loading</code> attribute instructs a browser to defer loading offscreen images until users scroll near them. It comes in three flavors: eager, auto, and lazy. Install this plugin and you can set the first image’s loading attribute and the loading attribute for all the subsequent images sent through <code>the_content()</code> in the plugin’s settings page.
Simple is Beautiful
There is no JavaScript or CSS included in the plugin. It just works in browsers that support the new <code>loading</code> image attribute.
For browsers that don’t support this new image loading attribute, that’s ok. You can still use whatever JavaScript-based image lazy loader you want as a fallback until browser support becomes a little more mainstream.

Native Image Lazy Loading

Automatically add the new loading attribute to images within your content to support native image lazy loading.

nigro.simone

This plugin, implementing “Lazy Load” technique, avoids download of the pictures and iframe that are not displayed on the screen (for example: images in the bottom of the page) until the user will display them. This improves load speed of page and save the bandwidth.
Configurations are not required! You just have to install it and after the plugin does it all, none further action it’s required. 
This plugin is very light: only 5 kb.

Speed Up – Lazy Load

this plugin just jumped my google speed test by 10 points !

thank you !

Improves load speed of page and save the bandwidth.

Native Image Lazy Loading vs Speed Up – Lazy Load