The WordPress Performance Challenge, part 6: Optimize images

I’ll tackle something that PageSpeed Insights has been complaining about since the start. Image optimization is the topic of this sixth part in the series.

There are a number of WordPress plugins to choose from when it comes to image optimization. One of the most popular seams to be EWWW Image Optimizer which was the one I installed first.
I ran into trouble immediately though. After activation, this error message appeared:

EWWW Image Optimizer requires exec(). Your system administrator has disabled this function

My friend Google explained that my host had disabled the exec() function for safety reasons. I realized that this was a roadblock I wouldn’t be able to get through.

WP Smush

After a bit of googling and researching, I decided to give WP Smuch a chance. It’s a free plugin but has a premium version that is more powerful. The free version is limited to images smaller than 1 mb. I think I’ll get away with that since it’s mostly screenshots that I upload to this blog.

I installed and activated the plugin and let it optimize all of my images. It actually had an greater impact on the test results than I thought it would.

PageSpeed Insights

  • Mobile: 69/100 (+7)
  • Desktop: 83/100 (+9)

WebPagetest

First view:

  • Load time: 2.638s
  • Start render: 1.981s
  • Speed index: 2032 (+8)

Repeat view:

  • Load time: 1.795s
  • Start render: 1.686s
  • Speed index: 1700 (-145)

PageSpeed Insights became very pleased about me optimizing the images and awarded me with many points!
In the next part, I’ll try to do something about the thing PageSpeed is complaining most about:

Eliminate render-blocking CSS in above-the-fold content