Ultimate 2022 Image Optimization Comparison – Best Image Optimization Plugins For WordPress

Back in 2017, we made a pretty good comparison of image optimizer plugins and services for WordPress, and we found out that ShortPixel was overall the best. Our analysis required a thorough exploration of the world of image compression for WordPress, and we did exactly that. Besides ShortPixel, we looked at other well-known image optimization tools, such as Imagify, Smush and EWWW Image Optimizer. We know that developing and maintaining the best image optimization plugin to speed up WordPress is a complex undertaking, therefore we believe it’s time to check the scores again to find out, objectively, which are the best image optimization plugins for WordPress in 2022.

Nowadays there are many other products that use a different approach, like taking the images and storing them on a CDN, from where they will be optimized and served. That’s the case of ShortPixel Adaptive Images, Optimole, WP Compress, Flying Images, etc. In this review, we’ll only focus on local optimization, where the images are compresses on your own server.

We are going to compare ShortPixel Image Optimizer with Smush, EWWW, Imagify, TinyPNG, Robin and reSmush.it, the most popular image optimization plugins in the WordPress repository in 2022.

Features comparison

Online image compressor

Wouldn’t it be nice to be able to see how the optimized images look before going to your WordPress dashboard and installing the plugins? Only three of the contenders offer this option:

1. ShortPixel: Online image compressor available
2. Imagify: Online image compressor available
3. TinyPNG: Online image compressor available

Unfortunately, there is no online service for the rest of the tools: Smush, EWWW Image Optimizer, Robin and reSmush.it.

Free plans: overview and limitations

	Free quota	Limitations	File size limit
ShortPixel	100 credits/month	None	None
Smush	Unlimited	No WebP/AVIF No backups No 3rd party integrations	5 MB
EWWW	Unlimited	No AVIF Only lossless compression	None
Imagify	20 MB/month	None	2 MB
TinyPNG	500 images/month	None	None
Robin	Unlimited	Slower support Slower compression No WebP No automatic compression No 3rd party integrations	5 MB
reSmush.it	Unlimited	None	5 MB

We can see that there are two groups of free plans: the plans that only have a limited monthly quota (ShortPixel and TinyPNG) and the unlimited plans that have a strong limitation feature-wise.

Basic features

After seeing what the free plans offer, let’s take a look at the basic image optimization features, the minimum we think any image optimizer should have to speed up WordPress: lossy compression, backup/restore functions, bulk processing and PDF compression. We’ll also list all the image formats every plugin supports.

PRO means that the feature is only available if you purchase a plan (paid feature).

	Lossy	Bulk	Backup	PDF	Formats
ShortPixel	YES	YES	YES	YES	JPG, PNG & GIF
Smush	YES	PRO	YES	NO	JPG, PNG & GIF
EWWW	PRO	YES	YES	YES	JPG, PNG & GIF
Imagify	YES*	YES	YES	YES	JPG, PNG & GIF
TinyPNG	YES**	YES	NO	NO	JPG & PNG
Robin	YES	YES	YES	NO	JPG, PNG & GIF
reSmush.it	YES***	YES	YES	NO	JPG, PNG & GIF

* Imagify no longer has a compression level to choose from. Instead, it compresses all images as much as possible and checks for quality loss to use a less aggressive method.

** TinyPNG allows Lossy but it’s the only compression method you can use. It’s not possible to use Lossless or another less aggressive method to optimize images.

*** reSmush.it compression only allows you to choose a level from 1 to 100; 1 being the poorest quality but most aggressive method, and 100 the opposite.

Flexibility

It’s important the plugin is flexible enough to adapt to all types of WordPress installations and environments. Now we are going to check if the plugins are compatible with WordPress multisite, WPML (the most popular solution for multilanguage sites) and/or WP Offload Media (offloads your media to external servers), and if they are able to optimize custom folders outside the Media Library.

PRO means that the feature is only available if you purchase a plan (paid feature).

	Multisite	WPML	Custom folders	WP Offload Media
ShortPixel	YES	YES	YES	YES
Smush	YES	YES	YES	YES
EWWW	YES	YES	YES	YES
Imagify	YES	YES*	YES	NO
TinyPNG	YES	YES	NO	NO
Robin	NO	NO	PRO	NO
reSmush.it	NO	NO	NO	NO

* Imagify is only partially compatible with WPML.

Advanced features

What if you want more from your image optimizer? Does it allow you to do the following?

• WebP generation and delivery: Google is increasingly pushing its WebP image format, which is proven to be more efficient than JPG/PNG. So, it’s important for an image optimizer not only to generate WebP images, but also to deliver them to your users.
• AVIF generation and delivery: We’ve already discussed in this article why AVIF is the next step in image optimization.
• CMYK to RGB conversion: Images for the web only need the RGB format and converting them from CMYK to RGB makes them smaller.
• PNG to JPG conversion: This can dramatically reduce the file size, especially if you have camera pictures that are saved in PNG format. 
• Resize original images: Recommended for large photos, like the ones taken with your phone. Saved space can go up to 80% or more after resizing.
• Exclusion rules: There are always some images that, for some reason, you’d like to keep unoptimized. Considering this, it’s important to have a section where you can exclude them.

PRO means that the feature is only available if you purchase a plan (paid feature).

	WebP	AVIF	CMYK to RGB	PNG to JPG	Resize originals	Exclusion rules
ShortPixel	YES	YES	YES	YES	YES	YES
Smush	PRO	NO	NO	PRO	YES	NO
EWWW	YES	NO	NO	YES	YES	YES
Imagify	YES	NO	NO	NO	YES	NO
TinyPNG	NO	NO	NO	NO	YES*	NO
Robin	PRO	NO	NO	NO	YES	NO
reSmush.it	NO	NO	NO	NO	NO	NO

* TinyPNG does not resize your images for free; it charges one additional compression.

Extra features

These are the special or unique features which give the particular “flavor” of each tested plugin.

• ShortPixel
  • While other image optimizers just optimize your images by running a simple command in the background, ShortPixel makes several optimization attempts on the remote servers using different techniques to find the best quality/size file, because not all images are the same.
  • Can optimize unlisted thumbnails. Those are thumbnails that are not registered in the metadata but only created alongside the other thumbnails.
  • Free for non-profits!
  • Can optimize your images even if your site is behind HTTP AUTH authentication.
  • You can use it together with ShortPixel Adaptive Images to serve your images from a fast CDN, freeing up server resources. Not only that, the plugin will serve adaptive images, so the exact needed size will be served to your users, and not the huge original image.
• Smush
  • Can detect and show incorrectly sized images to the site administrator. This way you can manually resize them to adapt to the image container.
  • Can export your settings so you can upload and apply them to your other sites in just a few clicks.
• EWWW Image Optimizer
  • Can add the missing width and height attributes to all images.
  • Can do faster optimizations by optimizing in parallel all generated images from a single upload.
• Imagify
  • Detects what theme you are using and easily offers you an option to optimize your theme images as well.
• TinyPNG
  • Allows you to keep specific metadata and strips out the rest of the image metadata. For example, you can keep only the copyright information.
• Robin
  • You can alter the optimization order. That’s useful if you want to optimize your Media Library from old to new.
  • You can choose a custom compression mode, from 1 to 100.

Optimization results

This second part of the review will focus on the actual optimization, because after all, a plugin can have a million features but still offer the worst results and not speed up WordPress. We’ll take a look at the numbers and see how much the plugins can compress the images and then we’ll show you the visual results.

The PNG format is less popular than JPEG, being used mainly for screenshots and images containing text. That’s why we’ll test 3 JPG images (large, medium and small) and 1 PNG.

Methodology

Since each of the plugins has different pricing and features, we need to set some parameters.

• We’ll make use of the compression level that offers the smallest file size possible. ShortPixel calls it Lossy, but every plugin uses their own naming.
• If the plugin offers it, we’ll strip out any metadata from the image. That’s usually the EXIF information.
• No PNG to JPG conversion will be done.
• The rest of settings will be left to default.

Image compression

	JPG-1 (2.6 MB)	JPG-2 (389 KB)	JPG-3 (5.8 KB)	PNG-1 (127 KB)
ShortPixel	162 KB 93.77%	102 KB 73.78%	1.7 KB 70.69%	40.9 KB 67.8%
Smush	449 KB 82.73%	356 KB 8.48%	1.9 KB 67.24%	39.5 KB 68.9%
EWWW	251 KB 90.35%	205 KB 47.3%	3.1 KB 46.55%	40 KB 68.5%
Imagify*	---	167 KB 57.07%	1.5 KB 74.14%	48 KB 62.2%
TinyPNG	251 KB 90.35%	205 KB 47.3%	3.1 KB 46.55%	40 KB 68.5%
Robin	251 KB 90.35%	158 KB 59.38%	1.2 KB 79.31%	42.8 KB 66.3%
reSmush.it**	251 KB 90.35%	158 KB 59.38%	1.3 KB 77.59%	42.9 KB 66.22%

We can draw a few conclusions from these results.

• ShortPixel is hands down the best image optimizer for large/medium JPG images, which is basically what 90% of the websites use.
• On the other end, also for the vast majority of images (large/medium JPG), Smush is doing a very poor job.
• Robin may be giving the best results for small images, followed closely by ShortPixel and Imagify.
• Almost all image optimizers give similar results with PNG images. The only exception is Imagify, that scores slightly lower than the rest.
• It’s interesting to see that both EWWW Image Optimizer (with its Premium Plus optimization method) and TinyPNG give the exact same results. This probably means that they use the same algorithms.

* We have used the trial periods of each service to make use of their best compression levels. Imagify does not offer trial periods or refunds, therefore we couldn’t fully test their compression levels.

** reSmush.it does not provide user-friendly compression level selection. As mentioned above, the user is the one who selects the compression level from 1 to 100. Since 1 would make the images completely unusable and 100 provides no compression, we set the value to 50.

Picture quality

Since each screen is different and beauty is in the eye of the beholder, we recommend you download the .zip file with all the images to see the results for yourself.

Pricing

Free plans are usually enough for personal sites, but if you have an online shop, a popular blog or any other kind of website that makes use of images on a more consistent basis, that means you’ll need to frequently optimize images to speed up WordPress. This requires that you purchase a plan from one the providers, so you can take advantage of all the features.

Ideally, we would show you a nice and well designed table comparing all the plans, but unfortunately, every provider uses a different pricing method, so we’ll have to use a good old list.

ShortPixel

ShortPixel has monthly and one-time plans, and each give you a quota with a certain amount of credits to optimize images. Each credit is used to optimize one image or thumbnail.

Monthly plans (2 months for free if paid yearly):

• $4.99/month – 7,000 credits/month
• $9.99/month – 16,000 credits/month
• $29.99/month – 55,000 credits/month
• $49.99/month – 100,000 credits/month
• $99.99/month – 220,000 credits/month

One-time plans:

• $9.99 – 10,000 credits
• $19.99 – 30,000 credits
• $29.99 – 50,000 credits
• $59 – 100,000 credits
• $99 – 170,000 credits
• $249 – 500,000 credits

All of the plans can be used for image compression on unlimited websites.

Smush

Smush offers three plans to optimize images:

• $7.50/month – 1 site
• $12.50/month – 3 sites
• $32.50/month – 10 sites
• $82.50/month – unlimited sites

All of the plans allow to optimize unlimited images, although their terms of service mention the following:

We reserve the right to suspend API access to users that use an unusual amount of API requests or resources that we feel may impact the services to other members.

There are also other limitations on the plans, like CDN bandwidth, but they are irrelevant for local compression, which is what this review is about.

EWWW Image Optimizer

EWWW has 3 monthly plans as well:

• $7/month – 1 site
• $15/month – 10 sites
• $25/month – unlimited sites

Like Smush, each of them includes unlimited local image compression and again, like Smush, the “unlimited” part has to be read carefully. In EWWW’s case, there is a “soft limit” of 25,000 images, and their terms state the following:

Unlimited Compress API keys are expected to be used reasonably and normally in order to protect the quality of service offered to all users. If we detect unusual API usage, we’ll email you to resolve the situation. In extreme cases, we may be required to restrict API usage.

In addition, EWWW has also one-time plans, starting from $3 for 1,000 credits. Higher plans don’t give a discounted price, so we are talking about $0.003 per credit.

Imagify

Imagify has only two plans to choose from, and like their free plan, they count the total size of images+thumbnails optimized, not the number of images themselves.

• $4.99/month – 500 MB
• $9.99/month – Unlimited

As with every “unlimited” usage, their terms of service state:

When we detect something out of the ordinary in your Imagify usage, we’ll contact you to discuss the situation and potential alternatives. In extreme cases, we may be required to limit the Service usage.

TinyPNG

They probably have the simplest pricing plans. You pay for what you use in a monthly basis, and that’s like this:

• $0.009 per image compression, up to 9,500 compressions
• $0.002 per image compression, from 10,000 compressions

Robin

Robin only allows to pay yearly for image compression, instead of monthly, and like ShortPixel, each plan gives you a maximum amount of images+thumbnails to optimize.

• $39/year – 5,000 images/month
• $89/year – 12,000 images/month
• $299/year – 55,000 images/month
• $499/year – 120,000 images/month

reSmush.it

Does not offer a paid plan, so the limitations are always present.

Conclusion

ShortPixel is the obvious winner, because of its clear and transparent pricing, its features and online image compressor, and most importantly, the actual results. If we had to pick a second solely based on the image compression results, it would be Robin. Robin has a good compression rate and if it’s not enough for you, you can also customize the quality level. However, you should be aware of their lack of features.

EWWW is also a good choice to speed up WordPress, and you can sense the passion of its creator. The main advantage of EWWW is also its biggest weakness: too many settings. Of course, this observation is highly subjective, but we believe that a tool to optimize images shouldn’t force users to make a lot of technical decisions.

At the other end of the scale, we find Smush. They have no online image compressor, their free plan is quite useless, offering almost no features, and the results in the paid plans are disappointing. It’s worth noting that the image optimization is not the main product of their parent company, and thus it’s understandable that they don’t get dedicated resources to work on improving it.

As WordPress’ popularity is rising, many WordPress users are looking for the best image optimization plugin for their needs. We hope that this guide will help you make a decision.

Images used for this test

IMG-1: photo by Brooke Lark, downloaded from Unsplash, resized 10%
IMG-3: photo by Aaron Burden, downloaded from Unsplash, resized 2%
PNG-1: screenshot taken by ourselves from the ShortPixel Bulk Optimization page on a WordPress site

The images IMG-1 and IMG-3 were previously resized, so we could test images having varied dimensions.

Disclaimer

We read and compared all the plugins’ settings, menus and websites, but it’s possible that we missed something or we got something wrong. If this is the case, please let us know and we’ll be more than happy to correct any errors.