The Why?

Let’s start with the why. Why did I perform these tests in the first place? There are plenty of tests that show how much WordPress Image Optimizers help with reducing the file sizes of images. But what I was really interested in is how much do they actually impact site speed.

So to perform these tests, I’ve progressively performed Speed Studies on our 8 Live WordPress Sites over the last 12 weeks to find which WordPress Image Optimization Plugin is truly the fastest?

The Speed Study Goal

My goal when I conduct Speed Studies is to find out which strategies are the best at improving site speed.

I’ll implement each strategy using the following approach:

  1. Setup the strategy on all 8 of our live test sites
  2. Then for the following 3 weeks, gather the load times from our Desktop Speed Test using GTmetrix. Each week we will test from a different location, starting in Dallas, then London and finishing off in Sydney.
  3. Next measure the impact of each strategy by comparing the average speed before and after.
  4. Ultimately decide whether the strategy works?

Fastest WordPress Image Optimizers – The Contenders

Let’s quickly run through the 4 Image Optimization Plugins that were tested:


Imagify, which is a freemium offering from the WP Rocket team, with over 50,000+ active installs.


EWWW Image Optimizer, which is a freemium offering with over 500,000+ active installs.


Kraken Image Optimizer is a freemium offering with over 20,000+ active installs.


ShortPixel Image Optimizer, which is a freemium offering with over 40,000+ active installs.

The Results – 23 Apr 2017

Let’s take a look at how our individual hosts performed with each Image Optimizer:

Fastest WordPress Image Optimizers - Individual Host Performance

Major Observations

  • First off, the results for DreamHost were excluded due to unrelated performance issues. These issues were unable to be resolved, which has led to them being replaced by Lightning Base for all future testing.
  • When we look into which plugins produced the fastest load times for each host, we find that:
    1. Imagify was fastest for HostGator, Web Hosting Hub & Namecheap
    2. ShortPixel was fastest for GoDaddy, SiteGround & Bluehost
    3. EWWW was fastest for InMotion Hosting
  • And the plugin with the fastest average across our 7 qualifying hosts is ShortPixel, with an average load time of 2.93s. Therefore the overall observation from where I sit is that if your looking for an Image Optimizer to help speed up your site, I would recommend going for ShortPixel.

And the Fastest WordPress Image Optimizer is…

Fastest WordPress Image Optimizers


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