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  …

Matthew Batchelder

SolidWP

Tanner Record

Justin Frydman

Site speed and performance optimization don’t have to be a complex task. With Solid Performance, simply install and activate, and the plugin will incrementally create static versions of each URL of your website for an instant performance boost.
<h4>How Solid Performance Increases Your Site Performance and Page Speed ✅</h4>
You’re busy, and you need to spend time building your website. In order to build well you need a solid foundation. Installing Solid Performance lets you optimize your site performance right away and start building sooner and faster without having to spend time configuring dozens of options.
A solid caching solution should not cause breakage with your favorite plugins. Solid Performance comes out of the box with smart plugin exception rules for pages that have dynamic content created by these plugins: 
* WooCommerce 
* GiveWP
With these smart defaults and page caching in place automatically, you can focus your time and energy on building and enhancing your website instead of struggling through dozens of caching settings.
<h4>What is Caching and how does Solid Speed leverage it ❓</h4>
There are several different types of caching
Solid Performance focuses exclusively on page caching, grabbing the HTML of your WordPress URLs and storing that in a secure directory. Then, when your visitors arrive at your site, the browser doesn’t need to run through PHP or hit your database again, it just serves up the static HTML, CSS, and JS files fast and simply.
<h4>How Page Caching Benefits Your Website Performance 🚀</h4>
As soon as you activate Solid Performance, your site will get an immediate boost. You’ll see benefits like these: 
🚀 Improved site performance (content delivery speed) 
🚀 Reduced drag on server load 
🚀 Measurable, quantifiable stats: lower bounce rates and higher conversion rates
When a site developer or manager is able to improve site performance for a client (for example), they are able to provide improved SEO results and meet a widely accepted expectation that well-run sites do not have slow download or content delivery times.

Solid Performance – Your No-Code Caching, Performance, & Page Speed Solution


Disclaimer: I do work for StellarWP. BUT, this plugin did speed up multiple sites I've installed it on, including my personal site devin.org



I suggest it for a "solid" page caching solution


Installed and it's like woah, fast fast fast

Solid Performance is a no-code solution for increasing the page performance of your WordPress website.

Featured Image Sharpen Up vs Solid Performance – Your No-Code Caching, Performance, & Page Speed Solution