There was a time when websites are used to be nothing but just a bunch of texts in a HTML file; but as time passes on, both the technology and internet speed grows, our perception about website also started changing rapidly. Now-a-days a normal webpage have more than 50% of it’s content as some kind of image, used to ornament the website design or to convey something in a easily understandable graphical manner. Though we all know that images are great for both making a website look better and to convey something in easy and engageable manner, but when it comes to speed, images are one of the biggest culprit to make your website load slower. As images are big in size and takes a bit of time to download all those images in your browser, so there is no surprise there.

One of the easiest way to fight this problem is by using proper dimension for your images and to optimize them. By “proper dimension” I mean don’t add a 1024px image in your webiste and then shrink it down via CSS to 100px. If you need a 100px image, upload that exact size only. There is no benefit for adding a large image if you are not going to show it in a large manner.

Now when it comes to image optimization some people often ask that why should we need it? Well you see, when any image been captured by any camera or been generated by any software like Photoshop or Illustrator, in both cases the image file consist of color data and metadata, most of which are no use for your website. But as those data are part of that file, it makes the size of that image file bigger. Now as we human can only see color wavelengths from about 390 to 700 nm, there are really no benefit of keeping the extra colors in your photos as they will just make your file size larger for no good reason. The same principle is used in video compression too, if you are more interested about these compressions, you can watch this fun video about how YouTube handles their video compression. Though it is not exactly same as image compression, but it will give you some perspective. 🙂

So obviously as WordPress is one of the most popular content management system (CMS) in the world and extremely easy to use, there are tons of image optimization plugin out there in the WordPress plugin repository. Now almost each of them has some sort of free version with extreme limitations and then you can upgrade to paid version for the full image optimization suite. So, today in this article I’m going to test out most of the popular WordPress image optimization plugin to find out truly the best WordPress image compression plugin in this image compression war. I’ll include both the free and paid version of these plugins in this test and in the end I will share my results with you guys along with the download link of the sample & compressed files.

The difference between Lossless & Lossy image compression

Before I begin further, I need to clarify one thing, i.e. the difference between the two types of image compression techniques, lossless and lossy. The reason I need to explain this is because a lot of my visitors who are reading this article may not be familiar with these terms and I’m going to use both terms a lot below, so this is really important that you know what they are and what are their difference.

What is lossless compression?

Well as the name suggests, lossless compression is a process which does not mess with your image’s color data. As I mentioned earlier, each image has some color data and metadata. In lossless compression, the compression algorithm only finds and deletes the unimportant metadata of your image files, like with what camera the picture was taken, what lens was used, what was the focal length, aperture, what was the geolocation of the image etc. These things are completely unnecessary for your website as in most cases you are never going to use these data on your website. So, the lossless compression algorithms finds and deletes these metadata from your images, making your image size smaller.

But you have to keep in mind that lossless compression doesn’t touch the color data of any image regardless of the color wavelength that can’t be visible by humans, it will keep those data intact. Generally with lossless compression you can achieve 2% to 37% size reduction on your images based on how many unnecessary metadata that image has.

What is lossy compression?

Lossy compression is a very sophisticated compression technique which requires many complicated mathematical algorithm, program and powerful server to handle them. That is why most image compression plugins allow lossy compression only on their paid plans and lossless compression for free plans. Anyways, with lossy image compression technique, the image generally get passed to a highly sophisticated program, that analyze all the data present within that image, including its metadata and the various colors that the image has. Then it simply removes all those color data that will simply not be visible by human eyes along with the unnecessary metadata.

As a result of this after optimizing an image with lossy compression system, you can achieve file size reduction around 40% to 97%, making the file really small but to a naked human eye who is going to see that image on your website just for few seconds or minutes, it makes no visual difference. Moreover as your file size are smaller, your overall website size gets reduced too and your website loads much faster.

But the problem with lossy compression is that, not all lossy compression company uses super high quality algorithms. So, in many cases if your image consist of thin texts, you may see some image degradation & pixelation. But again, as I have been using lossy compression on my site for years now, I have only see it happen with some compression company. But if you stick with a good compression company, you may never face any issues like this, but this is the only downside to lossy image compression technique.

My image compression test contestants

I’ve tried to take as many popular WordPress image compression plugin into my consideration, but still if I’ve somehow skipped the plugin you are currently using on your site or you love a lot, you can just simply download the sample files that I’ve used in my test and run it through your image compression plugin and then at last compare it’s size with the ones I’ve tested. Now I’ve actually used both of it’s free and paid version for the compression plugins I’ve used in my test. So I will break down the final result into two categories, one for the free image compression plugins and the other for their paid plugins. Here are my test contestants:

WP Smushit plugin has been created by WPMU Dev team and exists in the WordPress plugin repository for years now. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • Very popular plugin among old WordPress users
  • The user interface of the plugin is decent
  • Convert normal JPEG images to progressive JPEG image for faster loading experience
  • Allows only lossless image compression for the free version of the plugin and both lossless & lossy compression (Super Smush) for the paid version of the plugin
  • For the paid version users, email support is fast and fluid

Cons

  • The maximum file size allowed in the free version of this plugin is only 1MB which is extremely low in my opinion, but with the paid version you will have 32MB file size limit
  • There is no web interface to compress the images, you must need to use the plugin only
  • The plugin will only compress images that are uploaded by WordPress media uploader, you cannot custom specify any path to be compressed by the plugin. So, in short, you cannot compress images that are bundled with your theme or plugin folder
  • There is no WebP support with this plugin
  • The allowed image file formats are also limited to JPEG, PNG & GIF only.

Now let’s move on to our next contestant.

Optimus is relatively new image compression plugin in the WordPress marketplace. The optimus image compression plugin has been made by the awesome team behind KeyCDN content delivery network. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • Optimus supports creation of WebP format for your JPEG or PNG images. WebP is an extremely lightweight image extension created by Google to make image size smaller without losing any noticeable image quality. But the only downside is that WebP only supports in a hand few browsers (mostly webkit type) like chrome, opera etc. After you have WebP version of your image, you can use cache enabler plugin to incorporate it with your site properly.
  • Use fully secure HTTPS connection to transfer images back’n forth from your server and Optimus’s server.
  • Convert normal JPEG images to progressive JPEG image for faster loading experience

Cons

  • Optimus is just a lossless image compression plugin, there is no lossy image compression option even in the paid version
  • The free version of this plugin only allow max file size upto 100KB, which is insanely low but if you go with their paid version of the plugin, it will only get bumped up to only 5MB
  • Just like WP Smushit, there is no web interface for Optimus either, so the only way you can use this compression service is through their WordPress plugin
  • Just like WP Smushit, this plugin will also compress images that are only uploaded by WordPress media uploader, you cannot custom specify any path to be compressed by the plugin. So, in short, you cannot compress images that are bundled with your theme or plugin folder
  • Shockingly enough, even after you buy a license of Optimus, there is no special email or phone support for the paid users. You will only get a hand few previously written article, besides that if you need any other help, you need to contact them via WordPress free plugin support forum, just like a free user
  • While testing Optimus in several servers I’ve often encountered various HTTP error issues like 204 error, especially if I used it on a test site where I was using any other image compression plugin earlier before installing Optimus.
  • The allowed image formats are also extremely limited to only JPEG & PNG. That’s it!

Honestly, I wasn’t quite happy with the plugin. The result you will get with Optimus, you can even get the same (or even better result) with free plugins like EWWW Image Optimizer (will cover it below), so personally I really don’t see any reason for wasting money on this plugin. In-fact after my testing I was thinking about asking for a refund for this plugin as I’ll never use it on any of my personal or client’s site, but again despite being a paid plugin with no email support, I couldn’t asked for that either. In short I’ve wasted 19$ for this experiment.

Anyways, let’s move on to our next contestant.

Imagify is another relatively new image compression plugin in the WordPress marketplace. It has been created by WP Media team, the guys behind super popular WP Rocket cache plugin. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • Imagify supports both lossless (Normal Mode) and lossy (Aggressive & Ultra Mode) image compression in both free and paid version
  • Instead of having different version of a single plugin (Free & Paid), Imagify actually use the account API concept. So, even if you are just going to use Imagify for free, you still need to create an account on their website and in return you will get 25MB of free bandwidth each month to optimize your images. Then if you consider moving to the paid version, you just login to your Imagify account, give your card details and choose your monthly plan. That’s it. Pretty sweet and simple
  • Imagify also uses some unique billing concept for image compression bandwidth. If you don’t wanna go with a monthly plan and instead just wanna buy some bandwidth as a one time payment, you can do that too
  • Convert normal JPEG images to progressive JPEG image for faster loading experience
  • The user interface of imagify plugin is very engaging and intuitive. Clean flat design with some awesome design element. Really nice user experience
  • Imagify also comes with a web interface unlike the plugins mentioned above, so if you are working on a development project and quickly wanna compress some images, you can easily do that from the web image compression interface found inside your imagify account
  • Support for Imagify is great too

Cons

  • The max filesize limit in both the WordPress plugin and web image compression interface for the free imagify account is 2MB, which is average in my opinion. But for the paid account, there is no max file size restriction, which I haven’t seen in any other image compression plugins
  • There is no WebP support for Imagify in both the plugin & web interface (as of yet)
  • While testing I’ve seen that with the Ultra Mode of Imagify compression, sometimes there is quite noticeable amount of image degradation, especially if you have texts in your images. So, I will personally recommend Imagify users to stick with the Aggressive Mode for image compression without any noticeable image degradation
  • Just like WP Smushit, Optimus and others, this plugin will also compress images that are only uploaded by WordPress media uploader, you cannot custom specify any path to be compressed by the plugin. So, in short, you cannot compress images that are bundled with your theme or plugin folder
  • The allowed image formats are limited to JPEG, PNG & GIF only

Enough about imagify, now let’s move on to our next contestant.

Kraken.io is another image cempression plugin that many people use on daily basis. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • Kraken supports almost all possible image formats like JPEG, PNG, GIF & SVG, something that most other image compression plugin doesn’t
  • Kraken also supports both lossless & excellent lossy image compression. I haven’t seen any noticeable image degradation with Kraken’s lossy image compression
  • Kraken also uses almost the same kind of billing approach as Imagify does. You must need to create an account at Kraken’s website and then use it’s API via the WordPress plugin
  • Just like Imagify, Kraken also has web image compression interface that can be accessed from your Kraken.io’s account page
  • Convert normal JPEG images to progressive JPEG image for faster loading experience

Cons

  • There is no bulk optimizer within Kraken’s WordPress plugin. You have to manually select with old image you wanna compress and then run kraken. Alternatively you can run kraken for each media library page too. But if your site has tons of image with hundred of pages, you can truly see the pain in this
  • The max file size for the free accounts (both in web interface and plugin) is 1MB, which is relatively low in my opinion. But with the paid account the max file size limit gets bumped to 32MB
  • Kraken is relatively costlier than any of it’s competitors, starting from $5/mo just for 500MB bandwidth
  • There is no WebP file creation support in Kraken yet
  • The user interface of the WordPress plugin is not as good as plugins like Imagify or TinyPNG
  • Just like WP Smushit, Optimus and others, this plugin will also compress images that are only uploaded by WordPress media uploader, you cannot custom specify any path to be compressed by the plugin. So, in short, you cannot compress images that are bundled with your theme or plugin folder

Now let’s move on to our next contestant.

TinyPNG is a very trusted name in the image optimization industry. They are around in this compression game for years and has a reputation for generation the best compressed image without any noticeable image degradation. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • Has great user interface, especially in the bulk image optimization page
  • Uses almost the same billing structure like Imagify and Kraken. To use TinyPNG image compression with your WordPress site, first you need to apply for a developer API, which needs to be inputted within your WordPress plugin
  • Provides free web image compression interface at tinypng.com to anyone (no need for any account) for any number of images you want, just the max filesize limit is 5MB, which is enough in my opinion
  • Convert normal JPEG images to progressive JPEG image for faster loading experience
  • Supports third-party WordPress plugins like Retina 2x.

Cons

  • Unlike other image compression plugins, who relies on a bandwidth limit, TinyPNG counts each compression regardless of your image size. This can be both good and bad. Like for example if you are uploading a small 300px X 300px image, the size of the main file itself may be pretty small. So, if you mostly upload small images in your site then with a small bandwidth you can actually compress more images. But as TinyPNG counts the number of compression and not it’s size, so uploading a big and small image both is same to TinyPNG. This can be beneficial for people who mostly upload big images
  • With free TinyPNG account you will get 500 free compression each month with max filesize limit of 5MB. Now even if you started paying for TinyPNG API, the max file size limit will still remain at 5MB
  • There is now WebP image conversion support for TinyPNG
  • It support the least number of file types, only JPEG & PNG, nothing else
  • TinyPNG is a fully lossy compression system, it doesn’t provide any type of lossless compression whatsoever

Now let’s move on to our last contestant in this test.

Unlike the image compression plugins that are mentioned above which are mostly created by some companies and a team of developers, EWWW on the other hand has been created by a person single handedly named Shane Bishop. This is one of the most popular free image compression plugin in the WordPress plugin directory and is been used by thousand of people every single day. Here are a few pros & cons of this plugin as per my personal experience and consideration.

Pros

  • There is no shackle in the free plugin, you can use it as much as you like, as long as your server resource supports the compressions
  • The free version of this plugin uses your server resource to optimize your images in lossless manner. So, if you have any decent hostings, you will be fine with it, unless you need lossy compression; for that you need a  paid API key of EWWW Image Optimizer from their official website ewww.io
  • Support almost all file types like JPG, PNG & GIF for the free plugin and with paid API you can also optimize your PDF files too 🙂 I hope Shane brings SVG support pretty soon too
  • Has a ton of advance settings through which you actually insert any path of your server you like and EWWW will scan that path for any possible images and optimize that too, something that no other plugin provides
  • The max file size for the free plugin is complete depends on how much pressure your server can take. But for the paid API, the default file size limit is 50MB which is expandable just by sending a mail to EWWW Support
  • Convert normal JPEG images to progressive JPEG image for faster loading experience
  • Works brilliantly with almost all third-party WordPress image or gallery related plugins
  • It has WebP file creation support too
  • Excellent support for both free and paid version of the plugin

Cons

  • The user interface of both the plugin and website is a bit clunky in my opinion and not much intuitive like Imagify. So, for a non-techie user the out-of-the-box experience could be a little cumbersome. But I can I understand the reason behind it. As a single person has to do all, unlike other plugins who has a dev team, it is quite hard to concentrate on a better looking design and at the same time the actual quality of the plugin. I just wish their website be a little more sophisticated
  • There is no web interface for EWWW either, so you can only use it within your WordPress using the plugin
  • For the paid version of EWWW Image Optimizer, it also uses the exact same kind of billing approach as TinyPNG. So, it count the number of image to be compressed regardless of it’s size

A quick look at the feature difference of these plugins

So, as I’ve already talked a lot about each of these plugins and their pros and cons (as per my opinion), let’s take a quick look at the feature difference list for all of these plugins in a easily understandable tabular form.

TinyPNGKarkenImagifyOptimusHQEWWW (Paid)EWWW (Free)WP Smushit (Free)WP Smushit (Pro)
Max File Upload Size (inside Plugin/API)No Limit1MB (Free Acc) / 32MB (Paid Acc)2MB (Free Acc) / No Limit (Paid Acc)100 KB (Free Acc) / 5MB (Paid Acc)50MB (Extendable)Depend on Server1 MB32 MB
Max File Size (Web Interface)5 MB1MB (Free Acc) / 32MB (Paid Acc)2MB (Free Acc) / No Limit (Paid Acc)NNNNN
Web InterfaceYYYNNNNN
File SupportedJPEG, PNGJPEG, PNG, GIF, SVGJPEG, PNG, GIFJPEG, PNGJPEG, PNG, GIF, PDFJPEG, PNG, GIF, PDFJPEG, PNG, GIFJPEG, PNG, GIF
WebP SupportNNNYYYNN
HTTPS SupportYYYYYNNY
Progressive JPEG ConversionYYYYYYYY
Lossless Compression OptionNYY (Normal Mode)YYYYY
Lossy CompressionYYY (Aggressive/Ultra Mode)NYNNY (Super Smush)

In case the above table is not nicely readable in your screen, you can also download the image version of this comparison table.

Let’s begin with the real image compression test

Now as I’ve considered both the free and paid version of these plugins, I’m going to break this test result into two segments. One test with only the free plugins and the other with the paid version of these plugins. Please note, the plugins which gives the same behavior on the free & paid versions (like imagify, kraken, tinypng etc.) with only space difference, I’ve included them in the paid test section as there is no functional difference there. Also I’ve included Optimus in the paid plugin test as the free 100KB file size limit is insanely small to run on the free test. Also as most plugin supports JPG & PNG images, each test will be further segregated into two segments, a test for JPG images and a test for PNG images. That being said, let’s begin.

WordPress Image Compression Free Plugins Test

In my free plugin test, the contestants are EWWW (Free) and WP Smushit (Free). So, let’s begin with our JPG image test for these free plugins. Here are the image compression test result for these free plugins.

Image Name & DimensionOriginal SizeEWWW (Free)WP Smushit (Free)
Test-Image-2048X13651.24MB1.22MBSkipped (> 1MB)
Test-Image-710X473185KB185KB185KB
Medium-300X30067.3KB67KB67KB
Small-Thumbnail-150X15022KB22KB22KB

Here is a sweet before-after slider for your to see the visual difference between the original and the test image. As both of these free plugin uses lossless compression, so you are not supposed to see any kind of image degradation.

Original Image
EWWW Image
  • Original Size: 184 KB
  • EWWW Size: 184 KB (0% reduction)

Now as we are done with the JPG image test, let’s begin with PNG file image test. Again, here is the PNG image compression test result with the free lossless compression plugins.

Image Name & DimensionOriginal SizeEWWW (Free)WP Smushit (Free)
Test-Image-2048X13653.03MB2.87MBSkipped (> 1MB)
Test-Image-710X473362KB339KB362KB
Medium-Thumbnail-300X300119KB113KB119KB
Small-Thumbnail-150X15036KB33KB36KB

Now here is a sweet before-after slider for your to see the visual difference between the original and the test image.

Original Image
EWWW Image
  • Original Size: 361 KB
  • EWWW Size: 339 KB (6% reduction)

So, this ends our free WordPress image compression plugin test. So, as you have seen just like any other free image compression plugins, both of the above tested plugin uses lossless compression method, so there is no removal in the image color data (as explained above) and only unnecessary metadata has been removed. So, as a result, the percentage of image size reduction is pretty low. Now, it is time to begin our paid image compression plugin test.

WordPress Image Compression Paid Plugin Test

As explained above, in this segment the only paid plugin that is not capable of doing lossy compression is Optimis by KeyCDN and as Optimus provides as low as 100KB free file size limit in the free version of the plugin, it was really hard to add it in the above free plugin test. So, in this test except Optimus, all other plugin will be using their best possible compression level. So, let’s begin.

Just like we have done above, first we are going to run the JPG image compression test. So, here is the test results:

Image Name & DimensionOriginal SizeTinyPNGKarkenImagify (Ultra Mode)OptimusHQEWWW (Paid)WP Smushit (Pro)
Test-Image-2048X13651.24MB167KB153KB77KB1.22MB167KB226KB
Test-Image-710X473185KB49KB51KB22KB184KB49KB42KB
Medium-300X30067.3KB38KB25KB12KB66KB38KB15KB
Small-Thumbnail-150X15022KB12KB9KB5KB21KB12KB6KB

Now just like above, here is a before-after slider to check the visual difference between the original and compressed file.

Original Image
TinyPNG Image
  • Original Size: 184 KB
  • TinyPNG Size: 49 KB (74% reduction)

Now let’s begin with our last test, i.e. the PNG file compression test for the WordPress paid image compression plugins. So, here is the test result:

Image Name & DimensionOriginal SizeTinyPNGKarkenImagify (Ultra Mode)OptimusHQEWWW (Paid)WP Smushit (Pro)
Test-Image-2048X13653.03MB775KB791KB964KB3.03MB775KB907KB
Test-Image-710X473362KB107KB108KB135KB361KB107KB131KB
Medium-Thumbnail-300X300119KB37KB37KB46KB118KB37KB46KB
Small-Thumbnail-150X15036KB13KB11KB15KB36KB11KB15KB

So, now let’s take a look at the before-after slider for the visual difference so that you can see yourself if there is any kind of image degradation happening with the lossy image compression.

Original Image
TinyPNG Image
  • Original Size: 361 KB
  • TinyPNG Size: 106 KB (71% reduction)

With this, now our WordPress image compression plugin test ends. Now it is time to choose the best image compression plugin for WordPress.

Now let’s choose the best WordPress image compression plugin

Believe it or not, it is really hard to choose a winner as some plugins are really close to one another in some tests. If we look at the JPG image compression test result, everyone will think Imagify is the clear winner. But you have to keep in mind that in this test I’ve used the Ultra Mode of imagify which is not a recommended mode for any website, because with Ultra Mode if you look closely, the occurrence of visible image degradation is very high, so I will always recommend to stick with the Aggressive Mode in any production environment. In fact if you look closely at the before after slider above, you can see some minor image degradation with the Imagify compressed image. Again, this is obvious, as the name suggest, it is supposed to be an Ultra optimization which is not recommended.

Now, if you look at the next possible winner, it is an tie between EWWW Image Optimizer (Paid Version) & TinyPNG. The same thing happens in case of PNG optimization test too. In this test, Imagify is far behind, even with the Ultra Mode, and the winning plugin is a tie between TinyPNG & EWWW Image Optimizer (Paid Version).

Due to this tie, if we take the features of both possible winner plugin TinyPNG and EWWW (Paid) into consideration, it becomes much easier to choose the best image compression plugin for WordPress. It is undoubtedly EWWW Image Optimizer (Paid Version).

EWWW Image Optimizer has a ton load of features which no other plugin provides in the WordPress environment. I just wish that the user interface of EWWW Image Optimizer had been more intuitive and had SVG support along with a web interface for image compression. Maybe someday in future it will happen. Till then we have to live without it, but again the number of features provided by EWWW is really unparalleled to any other plugin out there, especially providing custom path to optimize any folder in your server.

Conclusion

I’ve spent a lot of time in this test to show you the honest truth about WordPress image compression plugins and their quality. I hope you guys will like it. There is always a myth among the newbie webmasters about whether or not to use lossy image compression for your website. I hope with this article you will see that if you choose a good compression system, there is no visible image degradation with lossy image compression. So, don’t listen to any marketing gimmicks and go with it, even if you have a photography website. But more importantly use a proper dimension image in your website. There is truly no benefit of adding a large image at the front end of your website if you don’t need that big image. 🙂

Feedback

What do you think about the above article? Have I missed your favorite optimization plugin? Do you use any of the above mentioned image optimization plugin? If you do, feel free to share your opinion about that plugin. Feel free to share thoughts about this important matter in the comment section below so that we can continue this conversation there.

Also if you want you can connect with me over twitter with my twitter handle @iSaumya. I’m looking forward to hear your thoughts on this and if this small piece of code helped you anyway. 🙂

Published by Saumya Majumder

Passionate, Hard Worker. Love to develop new things, Singing Songs, playing computer Action Games, tweaking with computer languages, Riding Bikes, Love long driving, love books, web & Photography. You can follow me on twitter @iSaumya

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