Best Free WordPress Image Optimization Plugin? WP Smush vs EWWW vs Kraken Comparison

Many website owners put focus and effort on writing great post content that they forget about optimizing images. Images make significant part of your site and having WordPress image optimization plugin installed is important step.

When it comes to saving bandwidth and accelerating your website performance, many would suggest you look into your site’s file structure. Things like scripts, style sheets, HTTP requests your site initiate, the redirects involved and lots of others are commonly recommended to look into.

While all these are indeed recommended, you also need to put into consideration the images you use on your site or blog. Images are a big part of your website. It’s what attracts readers, and ultimately drives traffic to your website. 

If you have high-quality images, then you need to optimize these images for the best end-user experience. This means compressing those images so that they load quicker.

Optimizing images without losing quality is a goal you want to accomplish. Optimized images can make your site’s loading time significantly shorter.

Optimizing is done by reducing the files size of images, reducing the resolution to what is needed and by stripping metadata. Not only does it help your site load faster, but it can also contribute to boost your rankings in search engines. Luckily, there are several tools and plugins available that can help you to automate the process.


 EWWW vs Kraken vs WP Smush

  • Plugin   
  • Free Version   
  • Auto-Smush Images On Upload   
  • Lossy Optimization   
  • Backup Original Images   
  • Optimize Images Individually   
  • Bulk Image Optimization   
  • Free Version Optimization Limitation   
  • Convert Files To Different Extension   
  • Optimize Images Outside Of The Media Library   
    Examples: theme images, BuddyPress, WP Symposium, and any folders that you have specified on the settings page.
  • Remove Metadata   
  • Offload Image Optimization   
    Let third-party server do optimization to reduce impact on your server.
  • Setting Image Optimization Level   
  • Scheduled Optimization   
  • Disable Automatic Optimization   
  • Disable Resizes For Certain Image Sizes   
    Wordpress, your theme, and other plugins generate various image sizes.
  • Filter Image Optimization By Folders   
  • Skip Images Based On Size   
  • Disable Image Optimization Based On Image Format   
  • Price Of Pro Version   
  • EWWW Image Optimizer
    EWWW Image Optimizer will automatically optimize your images as you upload them, optimize the images that you have already uploaded, convert your images automatically, and optionally apply lossy reductions for PNG and JPG images
  • Only in paid version
    Requires a $1 upfront payment (which includes 200 credits) and then charges per image
  • -
  • Only in paid version
    Requires a $1 upfront payment (which includes 200 credits) and then charges per image
  • Requires a $1 upfront payment (which includes 200 credits) and then charges per image.
  • Kraken Image Optimizer
    This plugin allows you to optimize new and existing WordPress image uploads through Kraken Image Optimizer's API. Both lossless and intelligent lossy optimization modes are supported
  • Only in Pro version.
  • Maximum Image Size 1 MB
  • Basic plan $9/month, Advanced $19/month, Premium $39/month, Enterprise $79/month.
    There’s also a Micro plan for $5 a month.
  • WP Smush
    WP Smush strips hidden, bulky information from your images, reducing the file size without losing quality. The faster your site loads, the more Google, Bing, Yahoo and other search engines will like it
  • Only in Pro version
  • Only in Pro version
  • Free accounts are limited to bulk smushing 50 attachments per request. Cant optimize images greater than 1MB.
    You will need to click to start a new bulk job after each 50 attachments.
  • Only in Pro version
  • Smush Pro is available as a standalone plugin for $19 a month.
    Alternatively, with a monthly WPMU DEV membership ($29) you can download Smush Pro along with 150+ other plugins and themes.


NOTE: The WordPress image optimization plugin comparison table above might not be up to date as time goes and plugins get updates and changes. For most accurate information, please check official website for each plugin.


WordPress Image Optimization Plugin Tips

The most commonly used image files are those with the extension JPG. They’re preferred by many due to the fact that they can apply heavy layers of compression (thus reducing file size dramatically) without a major effect on the end product.

JPGs eliminate redundancies that tend to cause file size bloat. This means they load faster, which is perfect for your visitors and for SEO.

When it comes down to the details, JPGs are not best choice. Compression algorithms applied to JPG images reduce the file size but also affect its quality.

Also, when the image is duplicated or saved, the quality degrades a little bit. The more saves you make, the more image quality declines. PNG images typically have much larger file sizes and are very high quality. Unfortunately, this means they load slower for users.

They’re lossless though, so you can duplicate and save the image as much as you want without losing any quality whatsoever. PNG allow transparent backgrounds, making them ideal for icons and logos.


When Should You Use JPG And When PNG?

Use JPGs for high quality photos and when you don’t need to make a lot of modifications to an image before uploading it. Use PNGs for photos with text, illustrations, signs, logos, icons, and any image you want to have transparency.

There are no rules for image file size limits, but for the most part I try to keep images under 100kb.


Lossy vs Lossless Compression

Lossy compression mainly analyzes your image and tries to pull out as many similar colors as possible in order to reduce the actual data that creates the image. This means that it attempts to throw out as much data as it can while keeping the general appearance of the image in tact.

This is very effective in getting smaller images, but the downside is that the final result is often a loss of the visual quality of the image. Lossless compression does not throw out any of the data that creates the image.

The science of it is really complicated, but the idea is to make an algorithm that represents that image as simply as possible for your browser to recreate. Think of it like creating a zip file.

You take a whole bunch of files and combine them all into a much smaller zip file. But once that zip file is unzipped, all the data is available to you again exactly as it was before it was zipped. That’s what lossless is doing to your images.


WordPress Image Optimization Before Upload

Besides selecting the right image file type for your situation, you also need to perform some additional compression activities. That will help speed up your site and make the end user’s experience pleasant.

When compressing images on your computer:

1. Duplicate the file – If you make a mistake, you’ll always have the original to go back to.

2. Reduce the size of the image – Scale it down to your desired size, crop it, and do whatever other modifications you want to make.

3. Compress image with a photo editor – I personally use Photoshop for all my photo editing activities. First I resize my images. When saving I choose option “Save for Web.”

Then you can also increase or decrease image quality (it will influence on image size) and give your image keyword related name.


WordPress Image Optimization Plugin After Upload

By image compression after upload I mean having installed WordPress image optimization plugin. There are various plugins available for this. Most popular and widely recognized free image optimization plugins are:

1.WP Smush WP Smush strips hidden, bulky information from your images, reducing the file size without losing quality. Installing and activating this plugin means it will compress all images you upload automatically, including those already on your site.

2. EWWW Image Optimizer – The EWWW Image Optimizer is a WordPress plugin that will automatically optimize your images as you upload them to your blog. It can optimize the images that you have already uploaded, convert your images automatically, and optionally apply lossy reductions for PNG and JPG images.

3. Kraken – This plugin allows you to optimize new and existing WordPress image uploads through Kraken Image Optimizer’s API. Both lossless and intelligent lossy optimization modes are supported. Supported file types are JPEG, PNG and GIF. Maximum file size limit is 16 MB.

There are many other WordPress image optiomization plugins like Optimus, ImageRecycle (see ImageRecycle review), ShortPixel, Optimole (check Optimole review), Imsanity, Hammy, etc. Also, you can do several things to compress your images after you’ve uploaded them to WordPress.

You can just choose one of the preset options before you insert the image into a post. You can usually select from Full Size, Medium, and Thumbnail. The original image size is still on your site’s server but a smaller version is called up when a visitor views your post, reducing load time.

If you want to prevent WordPress from compressing files or increase how much it compresses files, you can make a change to functions.php in your theme.

You need to add the following to your functions.php file:

add_filter( 'jpeg_quality', create_function( '', 'return 80;' ) );

The number (80) is the percentage level of compression automatically applied to the image. It’s important to note that following this method won’t compress images you’ve uploaded to WordPress in the past. It’ll only apply to new images.


Best Free WordPress Image Optimization Plugins

High-resolution images that are unnecessarily large in file size can drastically slow down page speed. Why waste resources and time when it’s possible to reduce image size without losing its quality?

Before even using these plugins, you should make sure that:

1. Your images are only as big as they need to be

The file sizes of images on your webpage can significantly affect the loading speed of your page. Unnecessarily large images, with big resolutions, will  take up resources, and ultimately will slow down the speed of your page.

If these images can be set to a lower resolution, or compressed to be smaller file size, then this will improve your website. To do this, images can be compressed, so that unnecessary information is no longer included, such as capture date and type of camera used.

2. Your images are given relevant names

This will boost your SEO. Images with corresponding names will be more likely to appear in search engines. It will help optimize your post, and directing traffic to your blog. This can be done simply, by adding a keyword into the title of the image.

If these tags are filled with keywords relevant to your article, it will be easier to find on a search engine, as they pick out key words when search the web.


#1 EWWW Image Optimizer

EWWW Optimizer runs lossless compression on images that are uploaded to WordPress automatically. It uses several free server tools to perform these optimizations. These tools are jpegtran, optipng, pngout, and gifsicle. It can either replace or keep a copy of the original uploaded file.

The plugin also features a way to convert files to a different extension, JPG to PNG, PNG to JPG or GIF to PNG, which can yield smaller file sizes. You can also optimize or bulk optimize previously uploaded images within the WordPress media library.




EWWW WordPress Image Optimization Plugin Review

After installing and activating plugin, you will see a list of tools that you need (jpegtran, optipng, etc.) and their status. Most hosting companies will probably already have it installed but in case they are not, you can isntall it from EWWW dashboard.

If you are having trouble make sure that your wp-content folder is writable, and then follow the plugin’s installation instructions. It will basically require you to copy some files from the plugin’s directory to your wp-content folder and then try the installation again.

If no additional steps needed, you will get the message: “All Clear.” The first section Cloud Settings can be ignored unless you are using EWWW’s paid cloud optimization service.

The next section, Basic Settings controls some global options. You can enable “Remove JPG Metadata” (recommended). In Advanced Settings, you can further tweak image optimization settings and even activate scheduled optimization.

The last section is Conversion Settings. This is for more advanced optimizations, where you will convert one file to another file type to decrease file size. You can check the box, next to “Delete Originals” if you want to remove the original files after they are converted.

Then you can choose which type of conversion you want to perform by default. You’ll be able to make these conversions on an image to image basis from your Media Library.

But if you enable JPG to PNG, PNG to JPG or GIF to PNG conversion then these will occur automatically on file upload. GIF to PNG is the safest of the three, though this will remove animations from GIF files.




Once everything is set-up, compression will occur each time a new image is uploaded to WordPress automatically.

If you go to Media -> Library you will see a new column next to your images labeled “Image Optimizer.”Here you can see how much each image has been reduced.

If you would like to optimize and image that has been uploaded previously, you can either click the “Bulk Optimize!” link in column, or check the boxes next to each image you want to compress, and then select “Bulk Optimize” from the Actions drop-down.

You can also optimize all of the images in your Media Library all at once, by going to Media -> Bulk Optimize. It will tell you how many images there are to optimize.

After you click the “Start optimizing” button a progress bar will load to show you the status as each image is optimized. The time that it takes will depend on how many images you have.




You can also go to Tools -> Optimize More. This will scan your WordPress install (themes, plugins, BuddyPress, etc.) for images that exist outside of your Media Library. You can then click the “Start Optimizing” button to compress these images automatically.

The plugin also includes special menus and options for BuddyPress, NextGEN, and the WP Image Editor class so it can be integrated with most, if not all, media plugins out there.


EWWW Image Optimizer Plugin Pricing

This is free image optimization plugin. Pro version is also available.

Pro version makes possible even more loosely compression of images. Requires a $1 upfront payment (which includes 200 credits) and then charges per image:

  • First 1,000: $0.005 per image
  • 1,001 to 5,000: $0.004 per image
  • 5,001 to 10,000: $0.003 per image
  • 10,001 and after: $0.002 per image

It doesn’t matter how big the images are, but how many you compress. So if you compress 1000 images it will cost you $5 and 10,000 images will cost you $20.

There is also a minimum charge of $1 a month, but if you don’t use any credits in a given month, you won’t be a charge. If you use less than 200 credits in a month, your $1 minimum monthly payment will give you credit for the following month.


Image Optimizer WordPress Plugin Conclusion

EWWW Image Optimizer is free to download from WordPress plugin repository. It is updated very often with new features and functionality. Image Optimizer plugin lets you compress images up to 16MB.

Like Kraken and Smush Pro, EWWW can automatically optimize images as you upload them to your site.

It can also optimize existing images and convert images automatically to the file format that will produce the smallest image size. You can also optionally apply lossy reductions for PNG and JPG images.

#2 Kraken Image Optimizer has a WordPress plugin which lets you optimize new and existing WordPress image uploads through Kraken Image Optimizer’s API. You can optimize file types like JPEG, PNG, and GIF. Maximum file size limit is 16 MB.

You can use your Kraken API key and secret on as many sites/blogs as you like. There is no per-site license!

Note: If you wish not to use the plugin, you can still upload and optimize your images online using the Kraken Web Interface Pro. It’s free.




Price: Kraken Image Optimizer plugin requires you to register to use. All plans start out as a free account, which comes with 50 MB of testing quota.

Here are the details of the premium plans:

  • Basic, $9 a month: 2GB of images per month, $4.00 per additional GB
  • Advanced, $19 a month: 5 GB, of images per month, $3.00, per additional GB
  • Premium $39 a month: 15 GB of images per month, $2.00 per additional GB
  • Enterprise $79 a month: 60 GB of images per month, $1.00 per additional GB

All plans include access to Kraken’s API, and a web interface where can upload one-off images for quick compression. The WordPress plugin is listed as included in the plan even though it’s already freely available to download from

There’s also a Micro plan for $5 a month, which includes 500MB of images per month and each additional GB is charged at $5.

All plans start out as a FREE Account which comes with 50 MB of testing quota. This is the usual Kraken free plan but you might want to look at the Kraken PRO features to make a decision.




Kraken Image Optimization WordPress Plugin Review is a web service where you send an image file, and it returns a compressed version of the file.

The images can use either lossless or lossy compression algorithms. Many images can be losslessly compressed to remove redundant or unneeded data in the image file. By sacrificing a small bit of image quality, lossy compression can drastically reduce image file size. offers a WordPress plugin that intercepts images from the media uploader before they are saved on your server and sends them to the web service to be optimized first.

The plugin also allows you to optimize existing images in your media library that haven’t been processed by Kraken plugin.

Other features include the ability to resize images using one of several strategies prior to optimization. But this you can only do within the web interface, not the plugin.

Installing and activating the plugin is a relatively straightforward process. Like Smush plugin, Kraken keeps things simple and doesn’t offer too much in the way of settings.




When you install the plugin, it adds a settings page to the Settings section in the WordPress admin sidebar. From there, you can add your API key and secret, choose if you want lossy or lossless optimization, and also allows new uploads to be automatically optimized. You need to login to your account on the Kraken website to access your API and manage your account and billing details.

The account dashboard provides an excellent overview of your total image compression statistics and average savings, though there’s no way to view statistics for individual images. After initially signing up for a free account you may realize the 50MB limit on images isn’t going to be enough.

#3 WP Smush

WP Smush is free image optimization WordPress plugin. It also comes in Pro version as a part of WPMU DEV membership. With a monthly or yearly WPMU DEV membership, you can download Smush Pro along with 150+ other plugins and themes.

It’s also important to point out that you need to have an active membership to use the plugin since it needs an API.




WP Smush WordPress Image Optimization Plugin Review

WP Smush is a WordPress plugin that allows you to optimize images without losing quality. It is very easy to use, and you can optimize your images on the fly as you upload them to your WordPress site.

For your older images you can go to Media » WP Smush to bulk smush 50 images at a time in free version. For beginners, it is an easy and simple way to optimize images and improve site performance. If you would like to utilize lossy and lossless compression, or backup of original images, you need to have PRO version.




WP Smush Free vs Pro

Smush Pro now lets you smush images up to 32MB. That’s more than enough for most people’s needs. The backend of the plugin includes options to auto-smush on upload (so you don’t have to smush images individually) and “super smush” for lossy optimization.

This last option promises two times more compression than lossless, with almost no noticeable quality loss. You can also choose to back up original images, though this will double the size of your uploads directory.

Smush Pro uses WPMU DEV servers to smush images, so you don’t have to worry about additional load on your servers. The easiest way to install Smush Pro is using the WPMU DEV Dashboard, since you need the dashboard plugin anyway to link your member API to the plugin.

Once installed, the plugin has just one settings page, which you can access from the Media section in the sidebar. Outside the settings page, you can view compression information and how much you’ve save for each image in the media library.


Free WordPress Image Optimization Plugin Alernatives

If you dont like above mentioned plugins and looking for another solution to optimize and compress images on your website, here are some alternatives to consider:


Optimole Image Optimization

Optimole comes in the free and paid plan. The number of images that you can optimize depends on image size and the number of optimizations. In Free plan you can optimize up to 1 GB of images, and have bandwidth of 10 GB.

The free plan uses Optimole custom made CDN built with seven locations. Paid plans have integration with Amazon CloudFront, with more than 130 locations around the globe. Plugin connects via API to OptiMole image optimization service to procces and optimize images.

Beyond the image compression and resizing Optimole also offers image acceleration through the plugin’s built-in CDN as well as built-in lazy loading.

For image compression, Optimole lets you choose from four different levels of compression quality. Those are Auto, Low, Medium and High. Optimole does all the compression on its servers, so it won’t slow down your site while compressing images.


ImageRecycle – Image And PDF Optimizer

I had opportunity to test another great image optimization tool – ImageRecycle. ImageRecycle comes with essential features like most other image compression plugins for WordPress.

But it also posses its own set of unique features that are not found in many of its competitors. For more information check ImageRecycle review in which I have compared it with other popular compression plugins.


Optimus – WordPress Image Optimizer

Optimus is another great free plugin for image optimization. This plugin reduces the file size of uploaded media files. Depending on the image and format, reductions in size of up to 70% are possible.

During the uploading process of images to the media library, the Optimus plugin simultaneously sends the images to the Optimus server.

Images are then processed and sent back in optimized form. Afterwards, the Optimus plugin saves the image version with a reduced file size in the media library.

The optimization of images is conducted in the background and outside of the view of the user. The image compression gains per file are displayed by Optimus within the media library in the form of a percentage value.

There are three different versions of Optimus:

  1. Optimus(Free) as base version with limitations (e.g. max of 100kb)
  2. Optimus HQ(Premium) with expanded functionality for personal projects
  3. Optimus HQ PRO(Premium) as professional solution for customer websites

More details about the features and the pricing model on



Like other cloud-based image optimization services, the ShortPixel optimizes your images on upload. The ShortPixel WordPress plugin sends the images to ShortPixel’s cloud servers (either automatically when you upload an image or when you use the bulk optimization option).

The cloud service does the crunching based on the settings you’ve chosen in the plugin’s settings panel.

The plugin pulls your image back from the cloud service into your site’s WordPress Media Library, replacing the existing version that’s there (you can choose to keep the original, untouched version as well).

ShortPixel system supports JPG, PNG, and GIF images (including animated), as well as PDF docs. The WordPress plugin is itself free, but the plugin won’t do anything by itself without connecting to the ShortPixel cloud service, which is where all of the heavy liftings actually happens.

There is a free plan for the cloud service, but it’s limited to only 100 images a month. That’s not a lot when you factor in the derivative thumbnails that WordPress generates automatically when you upload an image.

For most users, that’s enough to get a sense of whether it’s going to work for you, but unless you post very infrequently it’s probably not going to be enough.

To process more than 100 images a month, you’ll need to buy credits. There are two ways to do that: through a monthly subscription or with a one-off purchase of a credit bundle.


Best Free WordPress Image Optimization Plugin Summary

Taking into consideration options and features available, EWWW is best free image optimization plugin for WordPress.

But if you need simple image optimization plugin to compress your images on upload without too many setting you will never use, then I recommended WP Smush or Optimus.

If you decide to go for Pro versions, I would pick EWWW Image Optimizer or Image Recycle if you intend to use it on one or more sites. What about % of image optimization? Which plugin shows best optimization results?

I haven’t tested this. I only made comparison based on price and features. For compression success read this post (though it doesn’t take WP Smush into consideration).

If you’re concerned with your site’s load time, focusing effort on optimizing your images is way to improving site load and visitor’s experience. And if you need proper way to manage WordPress media library, then be sure to check my FileBird review.

DISCLOSURE: Posts may contain affiliate links. If you buy something through one of those links, I might get a small commission, without any extra cost to you. Read more about it here.

23 thoughts on “Best Free WordPress Image Optimization Plugin? WP Smush vs EWWW vs Kraken Comparison”

  1. that’s quite a lot of information. Thanks for the post and sharing your experience
    particularly useful information for me

  2. Hello there, I’d read all your posts about a comparison of various image optimization plugin. It’s awzm! They are superb in-depth and you covered all topics by providing real examples from your blog which helps to understand what you are explaining about your topic. Currently, I’m using WP Smush but I also have a plan to use EWWW because it performs additional optimization on our images that will improve site load time and visitor’s experience. I’m looking forward to your next post. Well done keep doing!

  3. Nice article. I used EWWW Image Optimizer before but it seems that sometimes slow down my hosting. Now I use Cheetaho image optimization plugin for WordPress. My website is not big, so I am happy using it. Also I get 500 free images per month.

  4. I am so delighted that I found your blog. I was just looking out for this topic.Images play a significant role in website’s SEO rankings.

  5. Wow, that’s quite a lot of information. Thanks for the post and the tools. I always rely on Photoshop, I did have to download all images and compress them “manually” in PS. Thank you for the list of these image compression plugins but consistent with me, ShortPixel seems to be the first. Presently, I’m using a unfastened tool called tinypng as well. It’s not a plugin but it enables a lot to compress snapshots without dropping their quality. Having a good picture compression plugin will save a lot of our time. I’m without a doubt going to attempt many compression tools that you listed and will share my experience…!!!

    As i said, I have personally used ShortPixels, Tinying and recently Optimus too, but now I have found permanent solution for image compression without any Subscription. I’m also planning to use Optimizilla website for online image compression. Its pretty cool and easy. I think everyone should try it atleast once. Also for newbie blogger, I would recommand WP Smush to start with. Then they can try other tools as they progress in blogging.

    Anyways, thanks for taking the time to write such an extensive review on this subject, it should be very helpful for many bloggers. Please keep sharing and good luck.

  6. Today I first installed ewww then later removed that and installed wpsmush. Now confused which one is better. so searched review and found this blog.

  7. I use photoshop and lightroom to export and optimise my images however further optimisation in WordPress with a plugin does help. Even an optimised image in something like Paintshop pro or Photoshop can be further reduced.

    While I used to like WP Smush they are expensive and their free version is terrible 50 images is useless. EWWW is reasonably priced and works well. In addition if you sign up to let them track how you use the plugin they add 500 free images to optimise.

  8. Thank you for this great comparison and so much useful information. I am currently using EWWW and I am pretty happy with it.

    1. Hey Ron,

      I agree. You do lose some quality. On some images it is significantly seen.

      For photographers showcasing their photos this is very important. That is why some plugins have backup option like Image Recycle.

      If you feel image quality was decreased you can always restore original image.

  9. Thank you for the great comparison of image optimization plugins. I was searching best image optimization plugin for my site. I think I will go with free version of WP Smush.

  10. Hello Kasa,

    I would like to add some value to this post. Recently I came across a very nice WP plugin. The new
    bloggers flood their blog with all the high-resolution images to make it nice and attractive. But for the matter
    of fact, that reduces the speed of the website and it takes a lot of time to load which hampers the user experience.

    Use ‘wp smush’ to reduce the size of images and keep the quality good. The free version will allow 50 images to
    smush at a time, then you need to start the process again for next 50 images. Premium version will take this
    restriction off.

    Hope this one of the nice ways to optimize an image.

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