How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

8 Min.
5 wordpress plugins to optimize images

Optimizing graphics and images for your WordPress website is a simple and important step to improving your website's loading speed. But you'd be surprised just how many WordPress users upload their original images without optimizing them. So you don't end up making the same mistake, I'm going to show you six popular and simple WordPress plugins today you can use as an image compressor.

As a website owner, you should always keep an eye on the loading time of your WordPress website. After all, a faster loading time has a positive effect on the user experience (UX) of your potential customers, your search engine ranking and ideally your conversions.

Why image optimization is so important in WordPress

Popular ways to steps to improve the speed of your WordPress site include: using caching plugins (or server cache), compressing data with gzip or Brotli, removing unnecessary plugins, switching to HTTPS and migrating to a faster host. Especially for WooCommerce shops with a lot of product images, shop owners are prepared to try out different optimization steps.

One important step that's often overlooked in loading time optimization is image optimization. What many people don't know is that as soon as you upload an image to your media library, WordPress automatically creates three additional formats: a large (post image), a medium and a small format (thumbnail).

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

So when you think you're just uploading one image, in reality four new files are actually being created - including meta information the server has to process. There are even themes that automatically generate 10 or more image sizes.

Try adding up all the different formats and the total number of images you use on your site. You'll see straight away why it makes sense to optimize your images for WordPress!

Resizing images is only the first step

One first optimization step is to compress your original images in e.g. Photoshop before you upload them. But to get the best possible results in terms of loading time, you need to compress all the images on your site, including image files generated automatically by WordPress.

The difference between "lossy" and "lossless" compression

When compressing images, a distinction is made between lossy and lossless compression. The terms are pretty much self explanatory:

With lossless compression, the quality difference between the image before and after compression is almost invisible. Generally speaking, only superfluous meta information is removed from the image file to save unnecessary kilobytes. With lossy compression, the image quality may suffer due to a reduction of colors and resolution. On the other hand, lossy compression can save significantly more file size.

5 WordPress image optimization plugins

By reducing the size of your original images before uploading them to your WordPress site, you're already ahead of many site operators. Plugins are the best way to retroactively optimize your existing media library and automate the compression of new images. I'd like to show you five popular plugins today to help you optimize your images.  

#1: Optimize WordPress images with Smush

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: over 1 million
Rating: 4.8 stars (5,500 reviews)
Supported formats: JPG, PNG, GIF (Pro: conversion to WebP)
Free of charge: image size max. 5 MB, bulk compressions of max. 50 images
Compression: lossless (Free) and lossy (Pro)

As evidenced by over one million installs and over 5,500 reviews, Smush by WPMU DEV is one of the most popular WordPress plugins for image optimization. Smush comes in a free version and a paid Pro version. Meanwhile, there's even the option to use Smush Pro as a separate tool (without WPMU DEV membership) for $60 per year.

What does the free version of Smush offer?

As with most plugins, the free version of Smush has some limitations. For example, you can only compress images up to 5 MB in size in the free version. Smush Pro has no such image size limits and, of course, offers many pro features like unlimited bulk optimization, CDN, lazy loading and WebP support. In addition, image optimization runs up to 200 percent faster in the Pro version according to WPMU DEV.

Another point to consider with the free version is that you can only compress losslessly. The highest compression level "Super Smush", which uses a lossy algorithm, is only available in the Pro version.

#2: Optimize images with the EWWW Image Optimizer

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: over 800,000
Rating: 4.7 stars (1000 reviews)
Supported formats: JPG, PNG, GIF, PDF, WebP
Free of charge: on own server only (without API)
Compression: lossless (Free) and lossy (Pro) possible

What does the Free Version of the EWWW IO offer?

Unlike the other plugins in this list, image compression in the free version of the EWWW Image Optimizer takes place on your server. This makes EWWW IO particularly attractive for many users from a privacy perspective. For the plugin to work, however, you need the exec() function. Many hosting providers, RAIDBOXES included, do not allow the exec() function for security reasons.

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The EWWW IO developers explains what the exec function and the plugin are all about in this article. If the exec function is not enabled for security reasons at your host (e.g. at RAIDBOXES), you can use the plugin's paid cloud-based plans.

#3: Optimize WordPress images with Imagify

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: Over 400,000
Rating: 4.5 (955 reviews)
Supported formats: JPG, PNG, PDF, Gif, WebP
Free of charge: image size max 2 MB, uploads max 20 MB per month, conversion to WebP.
Compression: lossy and lossless possible

What does the free version of Imagify offer?

Imagify is a plugin from WP Media, the company behind the well-known plugin "WP Rocket". In the free version ("Starter"), you can compress up to 20 MB per month, which according to Imagify equals about 200 images. The paid plans are "Growth" for $4.99 per month and 500 MB limit (about 5,000 images) and "Infinite" for $9.99 with no limit.

Imagify offers three different compression levels:

  • Normal: This is a lossless compression. The visible quality of the image is not changed.
  • Aggressive: This level is lossy, but with only a slight loss of image quality. According to Imagify, this loss is barely noticeable in most cases.
  • Ultra: This is the strongest compression level. It entails quality losses but saves the most space.

#4: WordPress Optimize images with ShortPixel

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: over 300,000
Rating: 4.6 stars (597 reviews)
Supported formats: JPG, PNG, GIF, PDF, WebP
Free of charge:100 images per month
Compression: lossy, "glossy" and lossless

What does the free version of ShortPixel offer?

The free version of ShortPixel allows you to compress 100 images per month. Images or files the plugin is unable to compress by more than five percent will not be deducted from your quota. Another plus is that even in the free version, lossy compression is possible and there's no limit on the size of the uploaded images.

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins
The three stages of image compression with Shortpixel

For those who want to optimize more than 100 images per month, Shortpixel offers seven plans with different image quotas: from 5,000 images for $3.99 per month to 16 million images for $1,000 per month. The three largest plans also include CDN traffic at various limits.

#5: Image compression with Compress JPEG & PNG Images

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: over 200,000
Rating: 4.4 stars (139 reviews)
Supported formats: JPEG, PNG, APNG (animated PNG)
Free of charge: 500 images per month
Compression: lossless

What does the free version of Compress JPEG & PNG Images offer?

Compress JPEG & PNG Images is the official plugin to the well-known online compression tools TinyPNG and TinyJPG. With the TinyPNG WordPress plugin, you can compress 500 images per month for free. Once the limit is reached, you'll be asked to upgrade and provide your payment details. There are no traditional subscriptions, no file size limits and you only pay for the number of images that are actually compressed. If you are in the upper range of the limits, a subscription model from another provider with unlimited optimizations may be the cheaper option.

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins
TinyPNG pricing

#6: Image optimization with Optimus

How to Optimize Images for WordPress: The 6 Most Popular Image Compression Plugins

Active installations: Over 60,000
Rating: 4.2 stars (68 reviews)
Supported formats: JPEG, PNG (WebP from paid version Optimus HQ).
Free of charge: image size max. 100 KB
Compression: lossless for PNGs and "slightly lossy" for JPEGs.

What does the free version of Optimus offer?

Optimus is an image optimization plugin from KeyCDN. The plugin offers three different plans: Optimus (free), Optimus HQ (premium) and Optimus HQ PRO (premium). An important limitation of the free version is the maximum file size of 100 KB. On the premium plans, the size limit is 10 MB. A secure connection to the server via HTTPS, WebP support and the use of the API is also only possible from the plan Optimus HQ. From a data protection point of view, however, Optimus has a decisive advantage - the data is processed on servers in Europe and deleted immediately after the images have been optimized.

The next step: Optimize images for SEO

Reducing the size of your images is an important lever for performance optimization. But what about your image optimization for SEO? Ronny Schneider shows you how to get the most out of image optimization in this article.

Conclusion: Image optimization with plugins saves time

You even save time in two ways. On the one hand, the manual optimization effort for you and your customers is eliminated. On the other hand, you improve the loading time of your website through automated image compression. In times when every millisecond counts in website speed, image optimization is a step you should make the most out of.

It's difficult to give a general answer as to which plugin is the best solution for you. Ultimately, it depends on how many of your images need to be optimized afterwards and how many new ones are added. If you only upload a few images per month to the WordPress media library and also include PDF files, ShortPixel is a good choice. If you don't want to rely on external servers to optimize your images and your host allows it, EWWW IO is a good option. For companies that produce content on a regular basis and upload a lot of images, WP Smush PRO, together with the other features of WPMU DEV, may be the better alternative.

The motto for maximum optimization is: "double is better"

If you want to spend as little time as possible optimizing your images, the paid plugin versions are probably the better choice. This way you don't have to constantly worry about exhausted megabytes or image quotas and the optimization runs automatically in the background.

If you can spend a little more time and want to get the most out of compression, you should even "double optimize". This is an approach we follow at RAIDBOXES as much as possible. Even before we upload an image to the media library, we resize it to the size we need and export it in the lowest possible resolution. In Photoshop, for example, there's an option to save images specifically for web use. You can find the command for this under "File" and "Save for Web". In addition, we use Shortpixel in Compression Type "Glossy", which automatically compresses every image uploaded to WordPress and removes unnecessary meta information.

I hope this guide features a plugin to fit your needs. If you have another recommendation for image optimization in WordPress, I'd be happy to hear from you in the comments.

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