mabujo

Featured Image Sharpen Up makes a tiny version of your featured post image and places it in the head of the page. 
As you scroll down the page, some JavaScript lazy loads the featured images in the background and replaces the tiny images as the full images are loaded.
You may have seen a similar effect used for images on medium.com.
Created on WordPress 4.4, but should work on earlier versions. 
Tested working on all Twenty Sixteen, Twenty Fifteen, Twenty Fourteen, Twenty Thirteen, Twenty Twelve and Twenty Eleven themes. Should work on other themes, but may need CSS adjustments, depending on theme handling of featured images.
Uses jQuery.Lazy(); (http://jquery.eisbehr.de/lazy/) and Hugh Lashbrooke’s plugin template (https://github.com/hlashbrooke/WordPress-Plugin-Template)
Plugin page : <a href="https://mabujo.com/blog/featured-image-sharpen-up-wordpress-plugin/" rel="nofollow ugc">Featured Image Sharpen Up plugin @ mabujo</a>

Featured Image Sharpen Up

This plugin helps increase the page loading speed of your site by replacing featured post images with a small inline image, and lazy loading the full  …

melmacaluso

Instantly, automatically and painlessly make your website faster by reducing image payload and lazy loading them.
<h3>What</h3>
Picafto makes your website faster by loading images after the rest of the content has been loaded. For the user it won’t make a noticeable difference but for Search engines (Google, bing, yahoo etc.), it will.
In resume Picafto offers you: 
-Automatic image load optimisation for vanilla WordPress editor. (whenever you upload an image in your page/post picafto will take care of it and automatically enqueue the loading when is appropiate to improve your page speed performance) 
-Same as above but for ACF fields (ACF being the main tool used by WordPress theme developers when it comes to building your website, meaning that if you had a website built by a dev this applies to you) 
-In addition you can add your own Picafto lazy loaded images with the sintax down below.
<h3>Why</h3>
One of the main ranking factors, is page speed. Meaning: if your website is slow you won’t rank as you would if it was lightin fast.
If they told you that there’s a something that makes your website twice as fast (if images are being used, that’s the main premise of the plugin) for free, in one click, instantly…would you use it?
<h3>Developer Friendly & ACF compatibile</h3>
Picafto does all the groundwork for you when it comes to lazy loading your images in both the vanilla editor and the ACF WYSIWYG editor but say you want some images to be lazy loaded the Picafto way? Well said? Done! Just swap the <code>src</code> with <code>data-picafto-load</code> in your images and Picafto is going to take care of the rest:
Before: 
 <code><img src="https//google.com/image.png" alt="image" /></code>
After: 
 <code><img data-picafto-load="https//google.com/image.png" alt="image" /></code>
If needed you can opt-out of the lazy loading by simply placing <code>data-picafto-off</code> as follows:

Picafto – One-click Lazy load images (ACF compatible)

Hello, @melmacaluso

Amazing Work, Sir and Great plugin to improve website speed. 
Can you develop lazy load for iframe or background-image for custom style. 

thanks

Great plugin to improve website speed

Instantly, automatically and painlessly make your website faster by reducing image payload and lazy loading them.

Featured Image Sharpen Up vs Picafto – One-click Lazy load images (ACF compatible)