Image Resize, new in Servebolt Optimizer Plugin 3.1

Last month we released a major update to our Servebolt Optimizer plugin. With version 3.0 we added complete support for Accelerated Domains and other features. Today, we are excited to release version 3.1 with the primary addition being the Image Resize feature. We’ve also added various other useful features and improvements.

Note: Before you upgrade, we always recommended to backup your database prior to testing any major release. 

What’s New?

In the previous post, we mentioned a few upcoming features which our engineering team has successfully incorporated in this release. Let’s look at them in detail. 

Image Resizing On the Fly

It is important to deliver images in the right size for an enhanced user experience. High-resolution large images might look good on desktops and larger screens but they are equally frustrating on small devices like smartphones where they take ages to download, render or cover half of the viewport.

The 3.1 version of the Servebolt Optimizer plugin now supports the auto image resizing feature of Accelerated Domains. This feature resizes and optimizes images at Accelerated Domains edge and enables you to serve all the correct sized images to your visitor’s browser on the fly. Since everything is handled inside the Accelerated Domains network, you save server resources such as bandwidth and disk space while your visitors enjoy fast web pages and asset delivery.

Activating Image Resize in the plugin is as easy as clicking on the Enable checkbox inside the Accelerated Domains setting in the plugin. After you’ve selected it, you will be presented with the following screen with further options:

Image Resize options
Image Resize Options screen in Servebolt Optimizer

Image resizing with Responsive Images support

The Responsive Images feature inside WordPress allows you to deliver the best image size for your screen by making multiple sizes of an image available to the browser. Responsive Images help improve image performance across different devices.

Responsive images have been supported by WordPress since version 3.3. Our newly introduced Accelerated Domains Image Resize feature improves, and enhances the built-in support for responsive images with its optimizations it does on the fly.

Want to give it a try?

To get Image Resizing enabled on your Accelerated Domain powered website, please get in touch with support.

The service must be enabled, and you must have the newest version of the plugin, for Image Resizing to work.

50% sizes automatically

We’ve added a setting in this update that enables you to automatically add half sizes of all registered image sizes in WordPress. For example, if your registered image size is 100×100 and you enable half sizes, then the plugin automatically adds 50×50 images. This is a very powerful feature when used in combination with Responsive Images in WordPress and WooCommerce. When using the combination of these two features, the browser will have more options that will help in displaying the perfect sized image to the end-user. Saving time on page load, bandwidth and transfer size.

Create custom image sizes easily

With the updated Servebolt Optimizer plugin, you can easily adjust the image quality and image sizes easily. Check out our documentation on what options you have available.

Similarly, you can also add custom image sizes without touching the code. This enables you to define custom image sizes based on the devices your customers use to visit your website or store, and truly optimize image sizes.

Quality setting and automatic format negotiation

The quality and format of an image are other important factors to consider as well. Without the right data and skills, it is difficult to manually handle the image responsiveness and optimization challenge. That’s why you have a quality setting available, enabling you to test different image quality settings without having to regenerate all thumbnails again.

In addition to that, Accelerated Domains has automatic format negotiation. This means that the browser tells Accelerated Domains if it supports modern image formats like webp, and if so the image will be delivered in a modern format. Resulting in faster loading and lower transfer size of images.

Why Responsive And Optimized Images Are Important?

Responsive images adapt well to different screen sizes and devices which ultimately improves the user experience of your website or online store. A perfectly sized image in the browser makes your product or website stand out while the optimized delivery of these images helps in saving your precious server resources and bandwidth of your visitor.

Free image resizing in beta

The Image Resize feature is still in beta. If you’re running Accelerated Domains on your site, you’ll get 50 000 resizes every month for free until the end of the beta.

Have you seen our Accelerated Domains solution?

It’s an easy set-and-forget service that will greatly improve four key elements of your site. Namely, performance, scalability, security, and sustainability.

Other Changes

Image Resize isn’t the only feature that made it in the Servebolt Optimizer 3.1 release. We’ve also improved existing features and added new ones.

Increased Cache Efficiency in Accelerated Domains

We have also introduced the new, and recently released as an open standard, header cdn-cache-control which helps to optimize cache efficiency further, especially for international websites.

Better Support for WP Rocket

Support for the WP Rocket was first introduced in the Servebolt Optimizer plugin version 3.0. We have teamed up with WP Rocket team to enhance the compatibility for WP Rocket integration even further. WP Rocket is now does not cache if the cache is enabled in the Servebolt Optimizer. Furthermore, both plugins will work alongside one another smoother now.

Yoast Premium Redirects Purging

When you’re running Yoast SEO Premium, we now support better cache purge for when a redirect is added or changed. This will make your redirections work instantly. 

Minimum PHP Version Restriction

Lastly, our Servebolt Optimizer plugin now only supports PHP version 7.3 and above. At Servebolt we support the latest and greatest software versions for optimum performance, security, and compatibility benefits. As such it made sense for us to have PHP 7.3 be the minimum requirement.


The 3.1 version of the plugin is now available but be sure to backup your website before testing it out. Feel free to reach out to our support team if you have any questions about this update.

Thomas Audunhus

Head of Product

Thomas has built some of the fastest WordPress and WooCommerce pages in Norway and knows exactly how to make this happen. As Head of Product at Servebolt, he makes sure our services are as performant as possible.

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