7 Best WordPress Image Optimisation Plugins Compared

Looking for the best WordPress image optimization plugin to speed up your site?

According to the HTTP Archive, images comprise about 50% of the file size of an average web page, so finding a way to shrink that can make a positive impact on your site's page load times.

An image compression plugin offers an easy way to fix that because you can continue to upload images like normal, while having the plugin automatically optimize them in the background.

To help you find the best image optimization plugin for your site, I went hands-on and tested seven popular options. For each plugin, I'll share its:

  • Key features
  • Interface (AKA real screenshots of how it works)
  • Performance (using the same test image for each plugin)
  • Pricing

What's more, all of these plugins also offer at least some form of free plan, though some are more generous than others.

Let's get optimizing…

How I'll Test These Plugins

To test the performance of these image optimization plugins, I'll upload and compress the same JPEG and PNG images with each plugin.

Some notes:

  • No resizing the image dimensions – only compression.
  • I will use the max lossy compression and lossless compression (two tests). I think this is the fairest way to do things, as each plugin handles things differently.
  • I will delete the EXIF data, when the plugin offers that feature.
  • The original JPG image is 294 KB.
  • The original PNG image is 272 KB.

I will also note when the compression level caused a noticeable change in image quality. If I don't mention the image quality, you can assume that there's little difference in quality (to the naked eye, at least).

ShortPixel

ShortPixel

ShortPixel is a popular freemium option that's active on over 100,000 sites.

As of a recent release, ShortPixel actually comes in two versions:

  • ShortPixel Image Optimizer – resizes and compresses your images automatically.
  • ShortPixel Adaptive Images – in addition to resizing and compressing images, it also serves your images from a CDN and dynamically resizes them based on each user's device. For example, someone on a Retina screen will get a high-resolution image, while someone on a smartphone would get a low-resolution image.

I'll test the regular image optimizer, as that's the most popular version. But ShortPixel Adaptive Images is also worth checking out if you like what you see.

Key Features

ShortPixel Image Optimizer

  • Automatically compress images using multiple levels of lossy or lossless compression.
  • Automatically resize image dimensions to a maximum that you set.
  • Compress JPG, PNG, GIF (including animated GIFs) and even PDF documents.
  • Convert images to WebP format.
  • Choose which image thumbnail sizes to compress.
  • Keep a backup of the original image.

ShortPixel Adaptive Images

  • Serve images from a global CDN.
  • Dynamically resize images based on the size of individual visitors' devices.
  • Smart cropping, to crop images while preserving the important visuals.
  • Automatically serve WebP images to browsers that support WebP.

Interface / Ease of Use

ShortPixel is pretty easy to use.

Once you install and activate it, you'll need to enter your email to generate a ShortPixel API key. You can re-use the same API key across multiple sites, which is convenient if you're running a network of sites.

Once you validate your API key, you'll get a simple settings area where you can:

  • Choose your desired compression level – two levels of lossy compression, along with lossless compression.
  • Choose whether to also optimize image thumbnails (the ones automatically created by WordPress).
  • Control whether to keep a backup of the original image and/or remove EXIF data.
  • Choose the max dimensions to automatically resize images, as well as how to crop images (if applicable– you can also just set a max width to preserve the original aspect ratio and avoid cropping).

ShortPixel interface

The Advanced tab lets you control smaller features, like whether to create WebP images, convert to JPEG, and more:

ShortPixel advanced

Once you make your choices, ShortPixel will automatically optimize new images that you upload, and you can also:

  • Bulk optimize existing images on your site.
  • Manually optimize images one-by-one

Performance

Max Lossy Lossless
JPG 80 KB 276 KB
PNG 80 KB 215 KB

Pricing

ShortPixel gives you a certain monthly quota for free. After that, you'll need to pay.

For free, you can optimize 100 images per month with no size limits. So if you just need to optimize a few large images, it offers great value.

After that, you can either purchase a monthly subscription or one-off image optimization credits. The cheapest subscription is $4.99 per month for up to 5,000 images per month, and the cheapest one-time package is $9.99 for 10,000 images.

Remember – this is for your entire ShortPixel account. That is, you can use your quota across multiple WordPress sites by using the same API key.

More Info / Download

Imagify

Imagify

Imagify is a freemium image optimization plugin from the same developers of the WP Rocket caching/performance plugin. As such, it slots in nicely with WP Rocket for a full-featured website performance suite.

Key Features

  • Automatically optimize images with three different lossy and lossless compression levels.
  • Create WebP images and serve them to browsers that support WebP.
  • Automatically resize images' dimensions.
  • Choose which thumbnail sizes to optimize.
  • Back up the original image.
  • Add custom folders outside your Media Library to optimize.
  • Keep a backup of the original image.

Interface / Ease of Use

Imagify has a really well-designed interface and is super easy to use. Like ShortPixel, you'll start off by generating an API key to connect to the Imagify service. Then, that will unlock the full interface.

At the top, you can choose your desired compression level. Like ShortPixel, you get two levels of lossy compression, as well as a lossless option. You can also choose:

  • Whether to automatically optimize images on upload and/or back up the original images.
  • Whether to keep EXIF information.

Imagify settings

Further down, you can configure:

  • Whether to create and display WebP images.
  • Automatic resize options. You can set a max width and then preserve the aspect ratio.
  • Which thumbnail sizes to optimize.

If enabled, Imagify will automatically optimize all newly uploaded images. And you can also bulk optimize older images, or manually optimize individual images.

Performance

Max Lossy Lossless
JPG 178 KB 276 KB
PNG 38 KB* 212 KB
*The lossy PNG number is impressive, but there was a noticeable difference in quality. I could not tell a difference in the lossy JPEG, though.

Pricing

Like ShortPixel, Imagify also gives you a certain free allotment per month. However, they calculate it differently.

Instead of doing it by the number of images like ShortPixel, Imagify limits you to 25 MB total per month. So if you have to optimize a lot of small images, the free plan might offer better value than ShortPixel.

After that, you can purchase one-time or monthly plans. The cheapest monthly plan is $4.99 per month for 1 GB of images, and the cheapest one-time plan is $5.99 for 500 MB of images.

More Info / Download

EWWW Image Optimizer

EWW Image OPtimizer

EWWW Image Optimizer is unique in where it optimizes your images. Most image optimization plugins – including ShortPixel and Imagify – connect to external servers via an API and perform the image optimization on those external servers.

EWWW Image Optimizer, however, uses your own server to optimize the images. This makes it free for unlimited usage, but it also means that you're going to be using your own server resources.

With that being said, the plugin also gives you the option of connecting via an API (if you pay), so you can choose the approach that works best for you.

For reference, I'm using the self-hosted version for my tests.

Key Features

  • Optimize images on your own server, or connect via the API for cloud optimization.
  • Optimizes JPG, PNG, GIF, and PDF.
  • Four different compression levels, though not all are available for free.
  • Automatically resize images to max dimensions.
  • Dynamically serve images via a CDN and resize them to a user's device (like ShortPixel's adaptive images). This is a paid service.
  • Schedule optimization to run at a certain time of day, which lets you schedule it for off-peak hours to conserve server resources.
  • Convert PNG to JPG, and vice versa.
  • Create and serve WebP images.

Interface / Ease of Use

Thanks to a recent redesign, EWWW Image Optimizer's interface is a lot nicer looking now.

However, it still gives you a ton of different settings. Now, that's not a bad thing. If you're into having pinpoint control, you'll like all those options. But if you're a casual user, you might feel a bit overwhelmed (in which case I would recommend something like ShortPixel or Imagify).

For example, you can see all those different tabs in the interface:

EWW Image OPtimizer settings

Performance

Max Lossy Lossless
JPG N/A 276 KB
PNG 80 KB* 212 KB
* This is the most aggressive lossy compression available for free, but the premium version unlocks higher compression levels.

Pricing

The core EWWW Image Optimizer plugin is available for free for unlimited usage.

You only need to pay if you want to:

  • Connect to the cloud optimization service for compression, CDN, etc.
  • Unlock all the compression methods and some other features.

Compression plans cost just $0.003/image. For example, you can compress 3,000 images for $9.

Then, the plan with the CDN costs $9 per month.

More Info / Download

Kraken

Kraken.io

Kraken is the WordPress plugin version of the popular Kraken.io image optimizer. Side note – I use the Kraken.io web interface when I'm optimizing images for client sites.

It's a nice simple option, though it lacks some of the advanced features in other plugins. For example, there's no WebP image support.

Key Features

  • Uses the Kraken.io compression service.
  • Lossy and lossless compression methods.
  • Automatically resize images to specified max dimensions.
  • Manually choose JPEG quality setting and chroma subsampling scheme.
  • Choose which thumbnails to optimize.
  • Preserve EXIF metadata.

Interface / Ease of Use

To get started, you'll need to generate a Kraken API key to connect your site to the service.

From there, you'll get a single settings page where you can configure which optimization method to use, as well as:

  • Whether to automatically optimize images on upload.
  • Automatic image resizing.
  • Which thumbnails to optimize.
  • Whether to preserve EXIF data.

Kraken interface

Performance

Max Lossy Lossless
JPG 246 KB 274 KB
PNG 73 KB 209 KB

Pricing

Kraken gives you a one-time 100 MB credit for free. After that, plans start at $5 per month for up to 500 MB of images and go up from there.

More Info / Download

Smush

Smush

Active on over 1 million websites, Smush is, by the numbers, one of the most popular WordPress image optimization plugins.

There's a big reason for that – it lets you optimize unlimited images for free using Smush's servers (not your own). There are some limits on that, but that's still pretty generous, and not something you find often.

Key Features

I'll start with the key features in the free version:

  • Automatically compress images with lossless compression. No lossy compression for free.
  • Automatically resize image dimensions.
  • Choose which thumbnail sizes to optimize.
  • Strip EXIF metadata.
  • Lazy load images for faster initial page load times.
  • Optimize images in external directories.
  • Bulk optimize 50 images at the same time.

And if you upgrade to the paid version, you'll also get these features:

  • Use lossy compression.
  • Serve images from a CDN.
  • Convert and serve WebP images.
  • Back up the original image.
  • Automatically convert PNGs to JPEGs
  • Automatically bulk optimize all old images.

Interface / Ease of Use

With Smush, there's no API key to connect to – you just activate it and dive right in. They even give you a nice setup wizard to configure the important basics.

After that, you get a nicely-designed interface where you can configure basic and advanced settings:

Smush settings

There are also some other tabs where you can configure functionality like lazy load.

Performance

Max Lossy Lossless
JPG N/A 289 KB
PNG N/A 272 KB*
*Smush declared my PNG test image as “Already Optimized” and didn't compress it.

Pricing

If all you want is lossless compression, the free version lets you optimize unlimited images (up to 5 MB in size each). So for lossless compression, this one is the best value.

However, if you want lossy compression, as well as all the other paid features, it can get a little pricey because you'll need a WPMU DEV membership, which costs $49 per month (though it also gets you access to all of WPMU DEV's other plugins).

More Info / Download

WP Compress

WP Compress

WP Compress is a newer WordPress image compression plugin that offers a generous pricing structure and a well-designed interface.

It also claims to offer “over-compression prevention”, though I'm not sure how to test that.

Key Features

  • Three different compression levels – two lossy and one lossless.
  • Automatically compress images on upload and bulk compress older images.
  • Automatically resize image dimensions.
  • Choose which thumbnail sizes to optimize.
  • Delete EXIF data.
  • Store backup of original images in the cloud (rather than wasting your own server space).

Interface / Ease of Use

Like a lot of the other plugins, you'll need to add your API key to the plugin to get started.

You can either start with the plugin's recommended settings or configure things yourself.

The interface is clean and looks great. There are just a few key settings, all of which are easily accessible:

WP Compress settings

Performance

Max Lossy Lossless
JPG 125 KB 240 KB
PNG 34 KB 50 KB*
*I'm not sure what's happening here because it doesn't seem to be lossless. I could see a slight reduction in quality in both lossy and lossless, though it was a lot less than what I saw with Imagify.

Pricing

WP Compress lets you optimize your first 100 images for free. After that, memberships start at $5 for up to 1,000 images.

However, their pricing has a unique (and generous) approach. Whereas most other tools count each thumbnail size as a separate image for billing purposes, WP Compress does not.

For example, if your theme has five different thumbnail sizes, a single image would take five credits at something like ShortPixel. But with WP Compress, it would only take one credit to optimize all the thumbnails.

More Info / Download

TinyPNG (Compress JPEG & PNG images)

TinyPNG

The aptly named Compress JPEG & PNG images connects your WordPress site to the TinyPNG and TinyJPG services to let you automatically optimize your WordPress site's images.

Though it doesn't offer unlimited free compression, it does offer one of the most generous free plans of any tool on this list.

Key Features

  • Only supports lossy compression, though it's not very aggressive and I couldn't see any drop in quality.
  • Automatically optimize new images and bulk optimize old images.
  • Choose which thumbnail sizes to optimize.
  • Automatically resize image dimensions.
  • Remove EXIF information.

Interface / Ease of Use

Like the others, you'll need to add your API key to get started.

From there, you can choose when to compress new images, as well as other settings like the thumbnails to optimize and whether or not to automatically resize images. There aren't a lot of settings – you're seeing everything in the screenshot below:

TinyPNG settings

Beyond that, there's also a bulk optimization tool to handle older images.

Performance

Max Lossy Lossless
JPG 144 KB N/A
PNG 72 KB N/A

Pricing

Compress JPEG & PNG images lets you optimize up to 500 images per month for free with no file size limits, which is pretty generous as far as free options go.

After the first 500 images, you'll only pay based on your usage. Your first 10,000 images cost $0.009 per image. Above that, you'll pay just $0.002 per image.

For example, if you need to optimize 1,000 images per month, you'll pay just $4.50 (remember – the first 500 optimizations every month are free).

More Info / Download

Which is the Best WordPress Image Optimizer Plugin for You?

To make it easier to see how each plugin performed, here's a full table recapping the results.

Remember:

  • The original JPG image is 294 KB.
  • The original PNG image is 272 KB.
Plugin JPG Lossy JPG Lossless PNG Lossy PNG Lossless
ShortPixel 80 KB 276 KB 80 KB 215 KB
Imagify 178 KB 276 KB 38 KB 212 KB
EWWW Image Optimizer N/A 276 KB 80 KB 212 KB
Kraken 246 KB 274 KB 73 KB 209 KB
Smush N/A 289 KB N/A 272 KB
WP Compress 125 KB 240 KB 34 KB 50 KB
TinyPNG 144 KB N/A 72 KB N/A
As you can see, there are a lot of similarities (sometimes even identical numbers). This makes sense because, in some instances, the plugins are using almost identical compression algorithms.

So which is the best image optimizer plugin for WordPress? Well, I have a few winners, depending on your needs.

For the best overall optimization plugin, I think the winner is ShortPixel for a few reasons:

  • Its compression numbers are solid.
  • Even the lossy compression didn't cause any noticeable drop in image quality.
  • It has a bunch of advanced features, like WebP support and PDF compression.

I'd say Imagify isn't far behind, though its PNG compression was a bit more lossy (though it also reduced the file size more).

Both tools offer free options, though the free plans are fairly limited.

If you're specifically looking for a free plugin that compresses images with an external API, I'd go with:

  • TinyPNG if you want to use lossy compression.
  • Smush if you want to use lossless compression.

And if you're ok with using your own server, EWWW Image Optimizer is also a great option that will let you optimize unlimited images for free – just make sure to schedule the optimization for an off-peak time if you upload a lot of images.

Have any questions about these image compression plugins? Ask away in the comments!

Colin Newcomer

Colin Newcomer is a freelance writer for hire with a background in SEO and affiliate marketing. He helps clients grow their web visibility by writing primarily about digital marketing and WordPress. You can hire him to write for your website.
Disclosure: Some of the links in this post are affiliate links, meaning that if you click on one of the links and purchase an item, we may receive a commission. All opinions however are our own and we do not accept payments for positive reviews.

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