Image Optimisation: What WordPress plugin is the best? — 4 of the best plugins

Phillip Stemann
12 min readDec 22, 2020

They say, “A single image is enough to tell the whole story”, which means that you don’t have to use thousands of words to define your point of view when you are using an exemplary image. Research says that people are more attracted to visual content than to written content.

Similarly, as a reader, I would prefer to read such articles with appealing images, or you can say I see the image first; if it attracts me, then I read the whole article. With this statement of mine, you can judge how a picture would significantly influence your entire content or website. This is the reason why images on e-commerce, travel, and media websites have become more and more popular over time.

According to the HTTP archive, more than half of the entire website (i.e., 64%) consists of images, which will directly affect your website’s load time if you don’t focus on “image optimisation”.

A quick tip before we dive into the best plugins; Always use JPG images as file format for you images, the reason being they take less space. Do only use PNG images as file type when you want to achieve a transparent background.

For those who have never heard the term “image optimisation”, I would like to make it a bit clearer.

“Image optimisation means to reduce the size of the image without affecting the quality and delivers the right format, resolution, and dimension.”

Phillip Stemann

Why is image optimisation necessary?

Image optimisation makes your website lighter, which enables your website to load within no time. Gomez and states that more people are intended towards those sites that has a load time within 2 seconds. If it takes more than 2 seconds, around 40% of the total visitors will leave the site and switch to your competitors website. This will drastically affect your conversions due to the increase in bounce rate.

Also, image file optimisation helps in boosting the website’s SEO ranking as it’s one of Google’s many factors, moreover it improves the user’s experience as they don’t have to sit and wait.

As Google has recently released a new major update to their search engine, where they focus a lot on User experience. Having images to load fast, will automatically create a better User Experience.

If you run a test on Google PageSpeed Insights, using your website, you will also see how important it is that your images, not only are optimised, but also are lazy loading.

How does it help in SEO?

In the year 2010, an article was published on Webmasters Blogs with a statement, “Like us, our users place a lot of value in speed — that’s why we’ve decided to take site speed into account in our search rankings”. This statement clearly indicates that only websites with faster loading speed will rank on Google because, just like its users, Google is also not interested in websites with slow speed.

As a website owner, you must have known how vital search engine rankings are. Now you know how pictures will play a significant role in your website’s ranking if they are appropriately optimised. If you don’t focus on image file optimisation for some reason, you will end up with a cumbersome website that takes time to load, resulting in less traffic.

So we can conclude that image file optimisation is one of the essential factors to increase your website’s speed.


This graph represents the correlation between page speed and Google search position.

In general, if you are successful in rankings on search engines, you can easily attract your audience’s attention, and the chances of conversions will increase. All this success depends on how well you have optimised your website, which includes doing your image optimisation.

To make it more precise here, I would like to give an example from your everyday life, i.e., “online shopping”, which is very common nowadays, and you all know that one of the best online platforms for shopping is Amazon. This website consists of 70% of images, still the website loads within seconds, and is very popular among people. One of the main reasons for the popularity of this website is loading time. Now see the other side of the story if the same website’s loading time is more than 3 seconds, about 79% of all buyers will not purchase from here again.


If you plan to reduce some images to speed up your web page, you are doing wrong by your visitors. This way, you will scare away your visitors because, as stated above, “visual content is more appealing than the written content”. Hence, you need to be more focused on image optimisation rather than image reduction.

The best Image Optimisation Plugins

So far, I have discussed the importance and role of image file optimisation. Now I will focus on the plugins that will help you with image optimisation in WordPress. Many plugins have proven to be a better help for image optimisation, but I have chosen 4 WordPress plugins to give you the best results. The reason for selecting these plugins is that they are very compatible with WordPress, and you don’t have to be a professional to use these tools, as they are extremely easy to use.


The team that designed one of the best caching plugins, WP Rocket, is behind this plugin. Imagify has all the essential features required to compress your image into a desirable size without affecting the quality of the image. Imagify offers three levels of image compression along with automatic image resizing.


Compression options

Normal: A lossless compression algorithm that won’t affect the image quality.

Aggressive: A lossy compression algorithm that can reduce image quality, which is not even visible mostly. You can choose the ‘aggressive’ mode if fast web loading is your priority over image quality.

Ultra: With ultra, you can make your image as small as possible. However, this compression comes with a price of reduction in image quality. It is also a lossy type compression algorithm.

With Imagify, you don’t have to worry about the loose in image quality as it creates a backup of the compressed image and original image. If you don’t like the image after it’s been compressed, you can easily restore the original image or you can test using another mode easily.

Automatic image resizing

Even compression wouldn’t help you much if you are uploading an image of massive width. Therefore, it is essential to resize the image first. This can be done in WordPress manually, however Imagify does the resizing job for you automatically to save you from the hassle of doing it manually in WordPress.

Bulk compress WordPress images

If you choose the ‘auto-optimise images on upload,’ all your newly uploaded images will automatically be compressed. Now what to do with the old ones? Don’t worry! Imagify has got you covered. By clicking on the ‘bulk optimisation’ option on the media panel, you can get all your images optimised in just one click.


3 compression algorithms from lossless to lossy offer you the flexibility to balance the right image size with great image quality.

You can convert your image to WebP format after you’ve done the optimisation.

Imagify is compatible with most of the image file types.

With the image resizer, you can resize your images directly through Imagify without the need for a separate resizing plugin.


Imagify allows you to optimise 25 MB of images per month only in the free version. This is very little, even if you just got started with your website.


For the free plan, you get 25 MB of optimised images per month.

Lite: At $4.99, you get 1 GB of optimised images per month.
Basic: At $8.99 you get 2 GB of optimised images per month.
Standard: At $19.99 you get 5 GB of optimised images per month.
Plus: At $39.99 you get 15 GB of optimised images per month.
Enterprise: At $69.99 you get 50 GB of optimised images per month.


With so many fantastic specifications at hand, Imagify is unarguably one of the best optimisation plugins. A huge plus is how well it works together with WP Rocket’s cache plugin which is unarguably the best cache plugins or WordPress. However, with insufficient data offered in the free plan, you’ll have to sign up for the paid version to experience uninterrupted services.


Shortpixel is considered the best WordPress Plugin by many of its happy users and for all the right reasons. The 3 compression types give you the liberty to choose between the image quality and website loading speed.


Compression options

Lossless: Lossless version does not change the image’s quality much and provides less image compression than the other two.

Glossy: This algorithm is specifically designed for professional photographers as it provides high-quality glossy images.

Lossy: High image compression means a reduction in image quality. This is what the lossy algorithm provides.

Automatic optimisation

This feature is added in ShortPixel by default, so you don’t need extra configuration. As soon as you post any image on your site, ShortPixel automatically optimises it without any extra hassle. It even optimises images that are added by other WordPress plugins outside the media library.

Upload any file size

ShortPixel can handle any file size of file and image, and compress it effectively. If you want to add super-high-quality images to your site and are looking for a good optimising plugin, then ShortPixel has got you covered.


ShortPixel offers you access to a dedicated image CDN. This means that when a visitor visits your website, ShortPixel will deliver the images from the server which is closest geographically to them, and this will help in latency in the image delivery.

Depending upon the visitor’s resolution and screen size, ShortPixel crops and resizes the images automatically.

The fantastic lazy loading image option loads the prioritised image first; then, the rest will load as the website scrolls further.


With so many robust features, there is the only con of this WordPress image optimisation plugin, and that is a low amount of images (only 100) per month.


Other than a free version, ShortPixel offers 3 paid plans.

Short: At $4.99, you can optimise up to 5000 images per month.
Large: At $9.99, you can optimise up to 12.000 images per month.
XXL: At $29.99, you can optimise up to 55.000 images per month.


ShortPixel stands tall in close competition with Imagify for the number one position on the list of WordPress image optimisation plugins. Due to a variety of powerful options, ShortPixel is becoming increasingly more popular amongst the web building maestros.

WP Smush

WP Smush is unarguably the most easy-to-use WordPress image optimisation plugin. You can get easy access to it for free. But, if you want to get your hands on some advanced features you can upgrade to its pro version. However, to get access to its pro version, you must sign-up for a WPMU DEV membership, which already costs $49 per month. This membership comes with many other plugins, which is kind of win-win but certainly not for your pocket.

WP Smush only uses a lossless compression algorithm which means the image quality is not affected while being compressed by the plugin. But with an upgrade to WP Smush pro, you can get more aggressive (lossy) compression algorithms.


Optimise images directly from the WordPress library

This image optimisation plugin is a great time-saver as it directly from the library makes it possible to optimise images, it is very convenient to use.

Image size detector

This feature of WP Smush helps in detecting any unoptimised image.


Without having to upgrade, you can compress unlimited images using the free version only.

WP Smush has all the features of top-ranking plugins like image resizing support and lazy image loading.


Using the free version, you can only optimise images up to 5 GB per file. Any file size higher than that requires the pro version.

Since the free version uses the lossless algorithm only, the image’s compression is somewhat limited.

Neither the pro nor the free version supports images that are bigger than 32 GB in file size.


The basic version is free, however, WP Smush offers 3 pricing models if you wish to upgrade.

Hobbyist: At $6 per month, you get 1 website, all WP Smush pro features and unlimited image optimisation, live onboarding support, and WP Smush pro ticket support.

Professional: At $9 per month, you get 1 website, all WP Smush pro features, unlimited image optimisation, live onboarding support, and 24/7 WP Smush pro live support. Moreover, you get access to Hummingbird pro and Uptime monitor.

WPMU DEV Membership: At $19 per month, you get all you get in the professional plan plus access to Additional Platform Benefits, such as SEO & Marketing Pack, Security & Backups Pack and much more.


WP Smush offers unlimited image compression with a free version, which makes it a compelling option. WP Smush’s easy to use features makes it a perfect pick for beginners or hobby bloggers.


Optimole has to be the most innovative WordPress image optimisation plugin. So, if you are looking for a fully automated image optimisation plugin, then Optimole is the ideal choice for you. All that you are required to do is install and activate the plugin, Optimole will take care of the rest.


Simple interface and configuration

With an easy-to-use interface, Optimole is one of the most straightforward WordPress plugins to use. The no-hassle configuration saves time for you to focus only on the content.

Adjust image optimisation according to the website visitors’ viewport. Optimole tailor optimise the images according to the user’s network or device. What basically Optimole does when it encounters slow internet connection, it automatically downgrades the quality of the image so that page loading won’t get affected by this.

Wholly cloud-based

Increased CPU usage means slower page loading. Optimole is 100% cloud-based, which means it does not hog your CPU. Using cloud-based technology makes the image optimisation and content delivery and image optimisation blazing-fast.


Using the unique dynamic image serving feature Optimole changes the image URLs with cloud-based URLs. Now all the images will be delivered from the Optimole server to the user. The result will be a high-quality fine image on the user viewport.

Optimole does not require jQuery or any other JavaScript libraries for the lazy-load mechanism, making the page loading even faster.


The biggest drawback of Optimole is that it does not store any compressed or resized images in the WordPress database. That means you won’t have access to the compressed image if you think of repurposing it elsewhere.


For an initial free plan, you get 5000 visits monthly. Other than this free plan Optimole offers 7 different plans:

Starter: At $22.9 per month, you get up to 25000 visits monthly.
Business: At $47 per month, you get up to 100,000 visits monthly.
Business 2: At $83 per month, you get up to 250,000 monthly visits.
Business 3: At $179 per month, you get up to 750,000 monthly visits.
Business 4: At $289 per month, you get up to 1.5M monthly visits.
Business 5: At $429 per month, you get up to 3M monthly visits.
Custom: The custom plan makes it possible to suit Optimole just for your need.


If you’re looking for the automation of your whole optimisation flow, then Optimole is the plugin choice for you. Considering the effective and fast image delivery and the less-hassle configuration makes Optimole a great option for you and your WordPress website.


No one wants to click on the website and wait forever for the page to load. Adding images to your content can make your page load slower. But, without any attractive images to present, no website can properly flourish. This is where image optimisation plugins come to play.

If you have to choose the best among the rest, then Imagify should be your priority, followed by ShortPixel. Imagify and ShortPixel have got all the powerful tools for swift image optimisation. However, if you are looking for an entirely automated plugin, then Optimole is the one for you. WP Smush provides you with the most easy-to-use tools; therefore, if you’re into technicalities, then WP Smush can be your best image optimising companion.

Now you have your image optimisation plugin, it’s time to focus on your caching. Read my top 5 best cache plugins for your website, to choose the right plugin for your needs.



Phillip Stemann

I am a web developer with 10+ years of experience. I believe that every project existing in the digital world is a result of an idea and every idea has a cause.