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5 Best Image Optimization Plugins for WordPress Tested on Real Images

Looking for the best image optimization plugin for WordPress?

To help you choose, we went hands-on with five popular options and ran our own tests.

See the results of these tests below:

Image optimization plugin for wordpress.
Test results for JPG images
Plugin Original size Optimized size Size reduced by
Optimole 345 KB 144 KB 58.1%
ShortPixel 345 KB 156 KB 54.8%
Imagify 345 KB 231.4 KB 32.9%
Smush 345 KB 337.4 KB 2.2%
EWWW 345 KB 337.4 KB 2.2%
Test results for PNG images
Plugin Original size Optimized size Size reduced by
Optimole 1.31 MB 45.5 KB 96.5%
ShortPixel 1.31 MB 287 KB 78.1%
Imagify 1.31 MB 534.9 KB 59.2%
Smush 1.31 MB 1 MB 23.7%
EWWW 1.31 MB 1.18 MB 9.9%
📸 See the JPG we used for testing:

We used a 1920×1280 JPG image sized at 345 KB and it looked like this:

Best image optimization plugin for WordPress JPG test image.

Optimole was the top performer, with a 58.1% reduction in the JPEG image size. ShortPixel was very close behind it with a 54.8% reduction in the JPEG size.

The other plugins were well behind Optimole and ShortPixel, though Imagify was much closer than Smush and EWWW Image Optimizer.

🖼️ See the PNG we used for testing:

We used a 2394×1810 PNG image sized at 1.31 MB and it looked like this:

Best image optimization plugin for WordPress PNG test image.

Our PNG image was completely unoptimized to start, which is a big part of how some plugins were able to achieve such large file savings.

Optimole won here by a large margin, with a whopping 96.5% reduction in file size. As with the JPEG file, ShortPixel wasn’t far behind, with a 78.1% reduction in file size.

Imagify came in at third again, with a 59.2% reduction, while Smush and EWWW Image Optimizer were fourth and fifth again.

👉 Quick recommendations and key takeaways:

Based on our experiences with these plugins, we recommend Optimole and ShortPixel as two of the best options for most people.

  • Optimole lets you leverage the modern adaptive image approach to optimize images in real time and serve them from a built-in content delivery network (CDN).
  • ShortPixel Image Optimizer works great for compressing images on your server. The actual processing happens on ShortPixel’s servers, but the optimized image files are served from your own site’s server.

If you want to learn more about image optimization in general, we have a whole guide on how to optimize images for the web. If you want to jump straight into the data and discover the best image optimization plugin, keep reading this post.

How we tested these image optimization plugins

To help discover the best WordPress plugin for image optimization, we went hands-on and ran our own tests.

We took two images, one in .jpg and the other in the .png format, and compressed them using the following image optimization plugins for WordPress:

  • Optimole
  • ShortPixel
  • Imagify
  • Smush
  • EWWW Image Optimizer

We did not enable fixed image resizing and we used comparable levels of compression (whichever lossy compression option the plugin recommends).

In some situations, the plugin uses an adaptive image approach, which means that the image will be resized for each individual visitor (rather than to a fixed resolution). This is part of how Optimole is able to achieve higher compression numbers.

To try to make it as fair as possible, we used the compression numbers for serving images to a desktop device (MacBook Pro 14 inch) with Retina support enabled. This is the highest-resolution image possible for most visitors, so it should make a fair test.

In real life, a plugin like Optimole would be able to achieve even higher compression numbers for visitors on small screens (e.g., mobile phones).

Best image optimization plugins compared in detail

Now, let’s dig into the plugins in more detail to help you choose the best plugin…

1. Optimole

Optimole is a powerful image optimization plugin that uses a unique approach compared to the other plugins on this list, which is a big part of how it was able to achieve the top performance.

Rather than optimizing the static image files on your server, Optimole optimizes images in real time and serves them from its built-in content delivery network (CDN), which is powered by Amazon CloudFront.

This means that Optimole is able to deliver a uniquely optimized image to each individual visitor to your server. This approach is called adaptive images. For example, someone browsing on a low-resolution smartphone would be served a smaller image than someone browsing on a 28 inch monitor with a 4K screen.

It can compress images, resize them based on each user’s device, convert them to optimized formats like AVIF or WebP, implement optimized lazy loading, and more. You can also enable smart cropping to smartly crop your images when needed.

Beyond the speed improvements, it also offers some unique features such as the ability to offload your image files to Amazon S3 to save space on your server (this is completely optional, though).

⚠️ Note – because Optimole uses this adaptive image approach, it’s a bit hard to compare to other plugins on this list in terms of performance. Again, Optimole optimizes images in real time for each individual visitor, so there’s no “single” compressed image file. In the real world, this means that Optimole will often perform even better than its results in this article. This is because we used a Macbook Pro 14 inch Retina screen for our test.

optimole plugin settings.

Key features ⚙️

  • Optimize images in real time and serve them through built-in CDN
  • Serve adaptive images that are optimized to each individual user’s device
  • Compress images using different compression levels
  • Convert images to optimized formats like AVIF and WebP
  • Lazy load all images on your site
  • Enable smart cropping to automatically crop images without losing important content
  • Serve CSS & JS through CDN (in addition to images)
  • Automatic GIF to video conversion
  • Option to offload images to S3 with a single click

Price 💳

Optimole has a free version that offers unlimited optimization for websites with up to 5,000 visitors per month. If your website gets more traffic than that, paid plans start at $19.08 per month for up to 50,000 visitors and go up from there.

2. ShortPixel Image Optimizer

ShortPixel is the most popular plugin on our list and also one of the top performers, coming in right behind Optimole in both tests.

The plugin has a simple setup. It needs you to register for an API key following which you are given access to general and advanced features.

There are tools for miscellaneous activities like clearing optimization errors, undoing all optimization, deleting image backups, integrating with Cloudflare, and removing all ShortPixel data when deactivating the plugin among other things.

shortpixel plugin settings.

Key features ⚙️

  • Optimize images at three different compression levels, with lossy and lossless options
  • Choose which image sizes to optimize
  • PDF optimization
  • Convert PNG to JPEG or WebP
  • Create custom media folders
  • AI-enabled smart cropping
  • Optimize retina images

Price 💳

The free ShortPixel plugin offers 100 free image credits per month. Each image size that you optimize will use one credit. So one uploaded image might use multiple credits if you want to optimize multiple thumbnail sizes.

To exceed that, you have two options:

  • One-time credit purchases – you can make one-time purchases of credit packages, starting at $9.99 for 10,000 credits.
  • Monthly unlimited plans – you can sign up for a monthly plan that allows unlimited usage, starting at $9.99 per month for a single site.

3. Imagify

Imagify is an image optimization plugin from the same team behind the popular WP Rocket plugin.

To access this image optimization plugin’s interface, you need to register for an API key following its installation.

Imagify has a simple interface offering general, optimization and display settings. The plugin lets you optimize images automatically as you upload them, and there’s also a bulk optimization tool to optimize existing images. You can also choose whether or not to store a backup of the original image file.

You can also choose from both lossless and lossy compression options, as well as convert image files to the WebP format.

imagify plugin settings.

Key features ⚙️

  • Automatically optimize images as you upload them
  • Use lossy or lossless compression
  • Convert images to WebP
  • Resize images to specified max dimensions
  • Select specific folders for targeted image optimization
  • Exclude default WordPress image file sizes

Price 💳

Imagify has a forever-free plan that lets you optimize up to 20 MB of images per month, with a max size of 2 MB for individual images. This will usually be somewhere between 100-200 images per month, though it depends on the size of the images.

The paid plans use a monthly billing approach – $4.99 per month for up to 500 MB or $9.99 per month for unlimited optimization. Both plans let you use Imagify on unlimited websites, so the unlimited plan can be a good deal if you have a lot of sites.

There is a fair use policy on the unlimited plan, but it shouldn’t be an issue unless you’re abusing it.

4. Smush

Smush is one of the most popular image optimization plugins at WordPress.org.

The free version supports both basic lossy and lossless compression, while the premium version adds an additional lossy option that can reduce image sizes even more.

In addition to compressing images, it also supports other optimization tactics like resizing images, lazy loading, and WebP conversion (premium version only).

The plugin automatically compresses existing as well as new images. It allows access to folders outside of the Uploads folder (where images are typically stored) so that images located anywhere on the website can be compressed by the plugin.

smush plugin settings.

Key features ⚙️

  • Compress images using lossy or lossless compression (you need the pro version to access the best lossy compression, though)
  • Resize images to a certain max dimension
  • Lazy load images
  • Convert images to WebP format (pro only)
  • One-click bulk restore to the original image
  • Show animation when images are lazy loading
  • Content delivery network (pro only)

Price 💳

Smush has a free version that allows unlimited usage for lossless compression and basic lossy compression. However, the bulk optimize tool for existing images only lets you optimize images in batches of 50 at a time, which means you’ll need to do a lot of clicking if you have a large library of existing images.

Because of the free plan, it could be the best image optimization plugin for users on a very tight budget.

To access advanced features like full lossy compression, CDN, WebP conversion, and integration with Amazon S3 and NextGen Gallery, among other things, you need Smush Pro. Smush Pro starts at $9 per month for use on a single site (billed annually). That includes unlimited image optimization, 5 GB of CDN bandwidth, and 5 GB of backup image storage.

5. EWWW Image Optimizer

EWWW Image Optimizer is a popular image optimization plugin that lets you choose between two different approaches:

  1. Optimize images on your server – this allows unlimited usage for free, but it will use your server’s resources to compress images. It also only supports lossless compression, which is part of why the plugin didn’t perform as well in our testing. We used this approach for our tests.
  2. Connect to the EWWW cloud – this does the image optimization on EWWW Image Optimizer’s servers. It saves your server’s resources and unlocks some new features (including lossy compression), but it will cost money.

After installation of the plugin, one of the first things you’ll notice on EWWW’s dashboard is the optimization score. It recommends the configuration best suited for your website.

The plugin optimizes new images automatically. As for existing images, the plugin’s Bulk Optimizer will take care of it.

Out of the box, optimization is enabled on the easy mode. For heavy optimizations, you can switch to the ludicrous mode.

Lazy loading and WebP conversion are disabled by default and have to be enabled manually.

ewww image optimizer plugin settings.

Key features ⚙️

  • Compress images using lossless or lossy compression
  • Resize images to certain max dimensions
  • Bulk optimization
  • Unlimited image optimizations
  • Background image optimizations
  • Add missing dimensions to images
  • Tailored optimization recommendations

Price 💳

If you’re okay with using your own server’s resources (and some feature limits), the free version of EWWW Image Optimizer allows unlimited usage with no image size limits, but only with lossless compression.

For automated optimizations and access to better optimization services like Compress API, Easy IO, and SWIS, you need to upgrade to the premium plugin that starts at $7 per month.

Which is the best image optimization plugin? 🤔

Installing an image optimization plugin to your WordPress website is a great way to boost your site speed.

But it’s hard to choose a plugin because of the sheer number of image plugins available there and the varying optimization settings they offer. We tested the five most popular image optimization plugins for WordPress and found that Optimole and ShortPixel Image Optimizer offer the best results for both JPG and PNG images.

For some other tips to boost your site’s performance, you also might be interested in our full WordPress performance optimization guide.

We also have an Optimole vs Imagify vs Smush vs ShortPixel comparison that compares some of these plugins in more detail.

If you have any questions about the best image optimization plugin for WordPress, let us know in the comment section below.

Don’t forget to join our crash course on speeding up your WordPress site. Learn more below:

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Sufia Banu

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