Improving PageSpeed Insights score: Optimising Images

Introduced in 2010, Google PageSpeed (also known as “mod_pagespeed”) which quickly become one of the most important and fundamental indicators as to organic SEO ranking used by the Google PageRank algorithm. 

Not to be confused with site load time, sometimes referred to as “time to first byte”, Google PageSpeed uses a variety of indicators to determine your site’s PageSpeed rank. PageSpeed Insights is a PageSpeed Tool developed by Google for site owners, webmasters and developers to check which of these indicators need to be improved in order to minimise the PageRank impact caused by not following good design, caching, minification and a variety of other industry standard practise techniques. 

Google PageSpeed Insights is free. To check the current impact it may be having on your site, simply click here and enter your website’s URL and click Analyze:

Google PageSpeed Insights will then give you a rating out of 100 for both the mobile and desktop versions of your site, given additional indicators for mobile such as site responsiveness.

Unlike the other 500+ Google PageRank algorithmic indicators which remain a guarded company secret, Google have been very transparent about the indicators that they use when it comes to Google PageSpeed. PageSpeed Insights gives you a Suggestions Summary list which tells you exactly what is causing the negative impact on your PageSpeed rating and how to fix it.

In this Article, Snug Site will be focusing on one of the simplest ways in which you can reduce the number of items in the Google PageSpeed Insights Suggestions Summary…

Optimising Images

WordPress sites tend to have a lot of images! Not only this, but WordPress insists upon creating 3 different image sizes for every image that a user uploads. In addition to this, certain themes and plugins (such as WooCommerce) generate their own image sizes for use. This can mean that for every image uploaded, you end up with 7-10 versions of the image in varying sizes.

In terms of the impact upon Google PageSpeed, image loading is a major contributor to slow page load times and a lot of this has to do with limited or no image compression as well as incorrect image formats. 

Let’s start by talking about formats. Not all image formats are equal. Portable Network Graphics or ‘PNG’ is a lossless format which typically scales more successfully at varying sizes than the alternative lossy image format Joint Photographic Experts Group or ‘JPEG’. “Lossy” basically means that the more you compress the image, the more the image will deteriorate. 

While PNG is invariably the better format and should be used if you are showcasing your major product line or selling artwork through your website, but in terms of the impact upon Google PageSpeed, the load times rarely make use of this format worth the SEO impact.  

So what is the solution if you already have a bunch of PNG images uploaded to your WordPress site? Install the PNG to JPG plugin and convert all of your existing PNG images to JPG. I recommend not compressing your images using this plugin.

The second part of the image optimization equation is compression. Image compression shrinks the size of your images meaning that users loading a page on your site have smaller file sizes to download and cache in their browser. Smaller file sizes mean faster page load times and an all around improved end-user experience. Some compression plugins also handle alternative image format conversions such as GIF to indexed PNG. In terms of recommending a compression plugin, it really comes down to preference, however the two best plugins that we have come across at Snug Site are WP Smush and EWWW Image Optimizer. At the time of writing, these are also the two most popular image compression plugins for WordPress, with around a million installs between them. Both plugins have their positives and negatives, but both achieve effectively the same outcome of compressing your images to improve end-user experience and ultimately, improve the PageRank impact of Google PageSpeed.

If you’d prefer that Snug Site tackle this aspect of your WordPress website performance; Get in Touch today.

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