WP Simple Thimble

This plugin embeds or in-lines image/css/js content into the page before it’s loaded. This really improves page load speed scores, and can really improve actual load time if either the network connection is not blazingly fast, server side caching is used, or a combination of the two.

Warnings that are commonly eliminated in page load speed testing tools include

Optimize images

Leverage browser caching

Remove query strings from static resources

Specify image dimensions

Minify JavaScript

Minify HTML

Avoid bad requests

Avoid a character set in the meta tag

Avoid landing page redirects

Defer parsing of JavaScript

Inline small CSS

Inline small JavaScript

Minify CSS

Minimize request size

Optimize the order of styles and scripts

Put CSS in the document head

Serve resources from a consistent URL

Serve scaled images

Avoid CSS @import

Combine images using CSS sprites

Use a Content Delivery Network (CDN)

Reduce the number of DOM elements

Make fewer HTTP requests

Minify JavaScript and CSS

Put CSS at the top

Put JavaScript at bottom

Avoid AlphaImageLoader filter

Avoid CSS expressions

Reduce DNS lookups

com/aadel112/simple-thimble, and you’ll note that these are all limitations that are actively being developed to be fixed.