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

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

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Many bloggers put much focus and effort on writing great post content that they forget about some important details. Like images. It is important to have WordPress image optimization plugin installed.

When it comes to saving bandwidth and accelerating your site’s performance, many people 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. Image optimization is a technique used by many WordPress sites.

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 they load in a flash.

Without losing quality, of course. It can make your site’s loading time significantly shorter.

This is done by reducing the files size of images, reducing the resolution to what is needed and by stripping metadata. Metadata is information such as when the picture was taken, what device was used…

Not only does it help your site load faster, but it can also help boost your Search Engine Optimization. This is achieved through adding alt and title tags to your images.

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.

Luckily, there are several tools and plugins available that can help you to automate the process.


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 greatly affect the loading speed of your page.

Unnecessarily large images, with big resolutions will  take up resources, and ultimately will slow down speed of your page.

If these images can be set to a lower resolution, or compressed to be a lower file size, then this will speed up 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 relevant 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.


WordPress Image Optimization PNG or JPG?

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 great 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 what?

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 basically 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 complex, 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.

Here are a few tutorials for GIMP, Photoshop, and Pixelmator to get you started.


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.


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.

This isn’t an exact science, however, and you still might end up with some pretty hefty image files.

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.


3 Best Free WordPress Image Optimization Plugins? WP Smush vs EWWW vs Kraken

Here are 3 best free WordPress image optimization plugins by my humble opinion!

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EWWW Image Optimizer



Pricing: Free image optimization plugin. Pro version 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 charge. If you use less than 200 credits in a month, your $1 minimum monthly payment will give you credit into the following month.


EWWW WordPress Image Optimization Plugin Review

EWWW Optimizer runs lossless compression on images automatically that are uploaded to WordPress. 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.


How Does EWWW Image Optimizer Work?

After installing and activating plugin at the top of the screen, 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. These extensions have also been bundled with the plugin.

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 installation again.

If no additional steps needed, you will get 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 “Remove JPG Metadata” which I recommend.

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 automatically compress these images as well.

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.


Image Optimizer WordPress Plugin Final Words

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.

By default, the EWWW Image Optimizer Cloud plugin uses lossless optimization techniques, so your image quality will be exactly the same before and after optimization.

If you decide to sign up for a premium account and downloaded the EWWW Image Optimizer Cloud plugin, you will have two new menu items to the Media section in the WordPress sidebar: Bulk Optimize and Unoptimized Images.

You will receive an email from EWWW with your API key in order to use Cloud options.

Kraken Image Optimizer



Price : Kraken Image Optimizer plugin requires you to register in order 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.


Kraken Image Optimization WordPress Plugin Review 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.

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

Maximum file size limit is 16 MB.

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.


Kraken Premium

Kraken has two plans you can enter, Kraken free and Kraken PRO.

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.




You can view the Kraken PRO Plans here.


Using Final Words 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 fairly 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.

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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 a nice 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.


WP Smush

Price: WP Smush is free image optimization WordPress plugin. It also comes in Pro version.

Smush Pro is available as a standalone plugin for $19 a month, which includes support and you can install the plugin on unlimited sites.

Alternatively, with a monthly 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 into order 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.

For beginners, it is an easy and simple way to optimize images and improve site performance.

But the performance difference is not as significant as you can get with other methods.

WP Smush gives you no control on how much you can optimize an image. While it does reduce the image file size, it is not the best solution.




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 individually smush images) 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 individual image in the media library.


 EWWW vs Kraken vs WP Smush Comparison

  • Plugin   
  • Description   
  • 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 a month, Advanced, $19 a month, Premium $39 a month, Enterprise $79 a 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.


ImageRecycle – Image And PDF Optimizer Plugin

I had opportunity to test another great image optimization tool – ImageRecycle.

ImageRecycle comes with basic 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 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


Best Free WordPress Image Optimization Plugin Final Words

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.

I personally use it on most of my sites.

If you decide to go for Pro versions I would pick EWWW Image optimizer if you intend to use it on one or two sites site. Mostly because of price, as you pay per image.

But if you intend to use Pro version of image optimization plugin and have many sites and images, then I recommend WP Smush.

You can go for WPMUDEV membership or pay this plugin $19 monthly and use on unlimited number of sites.


What about % of image optimization? Which plugin shows best results?

I havent 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.

Have you used any of above mentioned plugins? What are your favorite tools for WordPress image optimization?

Let me know in the comments below! If I made any mistake feel free to correct me.

About Article Author


Hello, my name is Matija but everybody calls me Kasa. I started this site to earn lots of money so that I never have to work again. Just lay down on a beach, drinking cocktails day after day while hot, beautiful chicks fight for my attention.Ok, now seriously. I love making websites, especially in WordPress. Hope reading content on this site you will find helpful tips, tutorials, comparisons, and product reviews for your business.

write a comment


  1. Vikas Singh
    March 14, 11:29 #1 Vikas Singh

    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.

    Reply to this comment

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