Images are still the heaviest resource on the web. According to HTTP Archive’s Web Almanac 2025, a median home page loads more than 900 KB of images on mobile, more than any other file type. And a page’s main image, the one that often decides its speed score, is still a JPEG more than half the time.
WordPress 7.1, released on August 19, 2026, brought a real change: compression and thumbnail generation can now happen in the browser, at upload time. But it still does not convert your JPEGs to WebP or AVIF by default. That choice has a history, which we tell below: in 2022, WordPress tried to make WebP the default, then backed off.
What core does not do, about ten plugins do, each in its own way. This comparison judges them on compression quality, how they deliver modern formats, what happens to your originals, and quota models that vary so much between vendors that prices are meaningless without an explanation.
What WordPress already does without a plugin
Responsive images and the big image threshold
Since version 4.4, WordPress adds the srcset and sizes attributes automatically: the browser picks the image size that fits the screen. Since 5.3, an uploaded image larger than 2,560 pixels is scaled down to that size and used as the “full” image, with the original kept alongside.
Each upload therefore produces several files: the original, a possible scaled copy, and up to six intermediate sizes, from 150 to 2,048 pixels. Keep that number in mind, it explains why plugin quotas melt so fast.
WebP, AVIF and HEIC: accepting is not converting
WordPress has accepted WebP uploads since version 5.8 and AVIF since 6.5, provided the server can process them. Since 6.7, HEIC photos from iPhones are converted to JPEG, if the server can read them. But an uploaded JPEG stays a JPEG: no version converts to a modern format by default.
To do it without a plugin, a filter is enough. This one, taken from the WordPress 6.5 developer note, produces AVIF files from uploaded JPEGs, if the server supports the format.
function filter_image_editor_output_format( $formats ) {
$formats['image/jpeg'] = 'image/avif';
return $formats;
}
add_filter( 'image_editor_output_format', 'filter_image_editor_output_format' );Check support under Tools, then Site Health, Info tab, in the media handling section. This filter only affects new uploads, and provides no fallback image for the rare old browsers.
WordPress 7.1: compression in the browser, and its limits
WordPress 7.1 hands compression, resizing and thumbnail generation to the browser, using the libvips library compiled to WebAssembly. The developer note reports JPEGs about 15% lighter, and less load on the server.
The conditions are strict: an upload made from the block editor, since uploads through the Media Library are still processed by the server, a recent Chromium-based browser, Chrome or Edge, an HTTPS connection, a device with more than 2 GB of memory and at least two CPU cores, and a download of about 13 MB for the processing module. Firefox and Safari fall back to the server. Images already in the media library are not reprocessed. To turn this mode off, use this filter.
add_filter( 'wp_client_side_media_processing_enabled', '__return_false' );In October 2026, only Imagify and EWWW document compatibility with this new mode in their changelogs. The others say nothing yet.
Lossy or lossless: what the settings mean
Lossless compression reorganizes the image data without changing anything that is displayed. Lossy compression removes details the eye barely notices, and saves much more. The Web Almanac 2024 gives an order of magnitude: about 2 to 1 for lossless, 10 to 1 for a classic lossy JPEG, more with modern encoders.
Each vendor has its own vocabulary. Imagify talks about smart or lossless compression, ShortPixel about Lossy, Glossy and Lossless, EWWW about Pixel Perfect and Premium, Smush about Basic, Super and Ultra, Optimole about automatic, high, medium or low levels. For a photographer’s site, favor the gentlest levels; for a blog or a store, the default lossy compression almost always works.
Be wary of the savings percentages vendors advertise: they are marketing figures. For a less commercial order of magnitude, use the WordPress 5.8 and 6.5 developer notes: WebP about 30% lighter than JPEG, AVIF up to 50% lighter.
How we ranked them
We read the directory listings, the pricing pages, the documentation and, when needed, the plugins’ settings themselves. Five criteria matter: compression quality and levels; the delivery method for modern formats; what happens to originals; the quota model and price; maintenance and readiness for WordPress 7.1.
A word on quotas: they are not comparable. Imagify counts megabytes, ShortPixel and TinyPNG count credits per file, each thumbnail using one, Converter for Media counts conversions, Optimole counts visits, EWWW counts bandwidth plus compression credits, Smush counts bandwidth. Since a single upload can produce seven or eight files, “100 credits a month” can cover only a dozen photos.
1. Imagify: the most stress-free default
What it does
Imagify, from WP Media, the publisher of WP Rocket, has more than a million active installs. It compresses on its own servers, with a smart mode by default or a lossless mode, and generates WebP and AVIF versions in every plan, free included.
Strengths
Modern formats are delivered through a <picture> tag or server-side rewriting, with an automatic fallback to JPEG. Originals are backed up by default in a dedicated folder, and a restore takes one click. Imagify skips a modern file that would be heavier than the optimized image, and it now optimizes thumbnails created by WordPress 7.1 in the browser.
Limits
The free plan caps at 20 MB a month, about 200 images according to the vendor, and at 2 MB per image. The quota is shared between all sites using the same key, and every optimized size consumes it. Imagify has no CDN of its own.
Price and audience
At the time of writing, the Growth plan costs $4.99 per month billed yearly for 500 MB, and the Infinite plan $9.99 per month billed yearly, or $11.99 month to month, with no limit. Imagify suits small and medium sites that want a single setting and to forget about it, especially alongside WP Rocket.
2. ShortPixel: the choice for agencies and large libraries
What it does
ShortPixel, with more than 300,000 installs, compresses in three modes, Lossy, Glossy for photographers and Lossless, and produces WebP and AVIF. It also processes folders outside the media library, converts HEIC to JPEG and offers AI-generated alternative text.
Strengths
One key covers unlimited sites, and one-time credit packs never expire: ideal for processing a large existing library. Three delivery methods are offered, and the vendor itself recommends server-side rewriting or its CDN over the <picture> tag. Processing continues in the background, with no tab open.
Limits
Each thumbnail costs a credit, and so does each conversion. Monthly credits expire after thirty days. The plugin does not work on localhost, and its version 6.5.6 in September 2026 hardened a component against an object injection reported by researchers.
Price and audience
At the time of writing, the free plan gives 100 credits a month. The unlimited plan costs $10.99 per month or $99.90 per year, and a pack of 30,000 credits $19.99 one-time. ShortPixel suits agencies, WooCommerce catalogs and large libraries that need catching up.
3. EWWW Image Optimizer: free and unlimited, on your server
What it does
EWWW Image Optimizer, with more than a million installs, is the only one in this comparison that compresses for free on your own server, with the classic image compression tools, with no volume limit. That requires the host to allow the PHP exec() function.
Strengths
It only replaces a file if the optimized version is lighter, keeps free local backups and offers a WP-CLI command for bulk processing. It offers the widest range of delivery options: one-click Apache or LiteSpeed rules, Nginx rules, JavaScript rewriting, the <picture> tag or a CDN. It also lets you disable WordPress 7.1’s in-browser processing.
Limits
Free local compression is mostly lossless, and strong savings go through the paid API. AVIF is only available through its Easy IO CDN. The rewrite rules do not work behind Cloudflare, and the <picture> tag ignores CSS background images. An object injection flaw was fixed in September 2026.
Price and audience
The plugin is free. At the time of writing, the paid plans, for unlimited sites, start at $8 per month or $80 per year. EWWW suits developers and technical owners on hosting that allows exec().
4. Smush: the familiar name, but the essentials are paid
What it does
Smush, from WPMU DEV, with more than a million installs and the most reviews in this comparison, offers three levels: lossless Basic, Super, which requires a free WPMU DEV account, and paid Ultra. It adds lazy loading and, in its Pro version, preloading and missing image dimensions.
Strengths
The Pro version’s direct WebP conversion needs no server rules, and its CDN with 119 locations serves modern formats. The option to back up originals lets you roll back.
Limits
The free version skips images over 5 MB and does not compress the full-size original file. WebP, AVIF and the CDN are Pro only. In August 2026, the CDN domain changed from smushcdn.com to assetcdn.net: if your site uses a content security policy, update it.
Price and audience
At the time of writing, Smush Pro costs $50 per year for one site, $75 for three and $100 for ten. Smush suits beginners who want a familiar name, and WPMU DEV members.
5. Optimole: everything on its network, nothing on disk
What it does
Optimole, with more than 200,000 installs, does not touch your files. It replaces your image URLs with URLs on its network, which returns to each visitor an image resized for their screen, in WebP or AVIF depending on their browser.
Strengths
No extra files on the server, no library to reprocess: everything happens on the fly. The number of images is unlimited, quality adapts to slow connections, and the vendor says it can coexist with another optimizer.
Limits
The price depends on traffic, with each unique visitor counted per day. The free plan stops at 2,000 visits a month, and beyond a paid plan’s limit, the vendor will ask you to move up. Your images depend on a third-party service.
Price and audience
At the time of writing, the Starter plan costs $22.90 per month or $229 per year for 48,000 monthly visits. Optimole suits image-heavy sites with modest traffic that do not want to add anything on the server. It pairs well with WordPress speed plugins.
6. TinyPNG: simple, for small volumes
What it does
TinyPNG’s plugin, with more than 100,000 installs, uses a single lossy engine, with no levels to set. It converts to WebP or AVIF, or automatically picks the lightest format, and delivers through server rules or a <picture> tag. It can keep copyright and location metadata.
Strengths and limits
The engine has a good reputation, and backing up originals has been available since version 3.8.0. But the free plan gives 500 compressions a month, about a hundred images according to the vendor, and fifty with conversion, since each image uses twice as many. Once the limit is reached, new uploads are simply no longer optimized.
Price and audience
Beyond the 500 free compressions, each compression costs $0.009, then less beyond 10,000 a month, at the time of writing. TinyPNG suits low-volume blogs and teams already using its API.
7. Converter for Media: WebP without touching the HTML
What it does
Converter for Media, with more than 500,000 installs, converts your images to WebP, and to AVIF in its PRO version. It does not recompress your original JPEG and PNG files: it is a converter, not a compressor.
Strengths
Its default mode changes no URL: the server returns the WebP or AVIF file instead of the JPEG, invisibly, if the browser accepts it. Originals are never modified, the generated files are stored in a separate folder, and the plugin removes everything it created when uninstalled.
Limits
Its default mode requires Apache or LiteSpeed with the right modules, or manual Nginx configuration; a “Pass Thru” mode, which goes through PHP, needs no server rules. Images served from an external CDN are not supported, except BunnyCDN. A flaw in its “Pass Thru” mode was fixed in January 2026.
Price and audience
WebP conversion is free. At the time of writing, the PRO version starts at $5 per month for 10,000 conversions a month, or $50 per year for 120,000 conversions, for unlimited sites. Converter for Media suits Apache or LiteSpeed sites that want WebP without paying or touching the HTML.
8. Modern Image Formats: the approach closest to core
What it does
Modern Image Formats is the WordPress Performance Team’s plugin, with more than 100,000 installs, free, with no account or quota. It generates intermediate sizes in AVIF if the server allows it, WebP otherwise, and uses them in content and in the Cover and Group blocks.
Strengths and limits
The uploaded original stays a JPEG or PNG, and a modern file heavier than the original is discarded. But it does not compress originals, has no CDN or bulk processing, and only affects new uploads. To convert existing images, you need to regenerate thumbnails, for example with wp media regenerate, a command covered in our selection of WP-CLI commands.
Price and audience
Free. Modern Image Formats suits developers who want to stay as close as possible to WordPress, on hosting able to produce AVIF, and anyone who refuses third-party services. It is the direct descendant of the story that follows.
The real case: the day WordPress tried to make WebP the default
From March to September 2022, the WordPress Performance Team tried to make WebP the default format for every site. The episode is documented step by step on the official developer blog, in the code history and by WP Tavern. It shows that the choice an image plugin makes for you is far from trivial.
The proposal
On March 28, 2022, Adam Silverstein published the proposal: for every uploaded JPEG, WordPress would also generate WebP versions of every size and serve WebP to visitors. Expected saving, about 30% less weight. Acknowledged cost, uploads twice as laborious for the server and about 70% more storage. The proposal received 154 comments in two weeks.
The first retreat, then the data
On April 12, the team announced it had heard the criticism and opened research into upload impact and compatibility. On June 30, it came back with data: a survey of seventeen hosts, according to which, at large hosts, the vast majority of sites would be unaffected even with doubled storage, and near-total compatibility across browsers and email clients.
The plan was revised: WebP only for WordPress’s own sizes, a file kept only if it is lighter, a fallback image for the rare old browsers. On July 21, 2022, the code went into WordPress, slated for version 6.1.
The objection and the decision
In August, Andrew Ozz, a WordPress lead developer, objected. Why twice as many files, when half would never be used? He saw the extra load at upload time as having serious consequences: failed uploads and more support requests. Adam Silverstein answered that an image is served vastly more often than it is uploaded.
On September 6 and 7, the team switched to a lighter version, with intermediate sizes in WebP only. On September 11, Matt Mullenweg made the call: forcing this conversion on every site when it updated to 6.1 was too much for now. He proposed turning it into an official plugin. On September 19, the code was removed.
What remains
WordPress 6.1 shipped on November 1, 2022 without WebP by default. The module became the WebP Uploads plugin, renamed Modern Image Formats, which today produces AVIF by default. WordPress has accepted AVIF since 6.5, converted HEIC since 6.7 and compressed in the browser since 7.1. But four years later, the rule has not changed: no automatic conversion to a modern format.
What the story teaches
A format change multiplies files and load on every hosting account. For a setting that touches a considerable share of the web, those costs weighed more than the bytes saved. Yet that is exactly the choice every image plugin makes for you: generate a second format or not, keep originals or not, deliver through rewriting, a tag or a CDN. Read its settings before launching a bulk optimization.
9. Jetpack Boost: a free image CDN, with no quota
What it does
Jetpack Boost, from Automattic, with more than 200,000 installs, works without the Jetpack plugin. Its free Image CDN module serves your images resized and in WebP from Jetpack’s worldwide network, without changing your files or your database.
Strengths and limits
No quota to manage, nothing to bulk-process. On the other hand, the documentation does not mention AVIF, images over 50 MB are not processed, and cached images cannot be purged automatically. The paid version adds a per-format quality setting.
Price and audience
The image CDN is free. At the time of writing, paid Jetpack Boost lists at $239.40 per year. Jetpack Boost suits sites that want a free image CDN with nothing to manage, especially if they already use Automattic’s tools.
10. Image Optimization by Elementor: convenient, but poorly rated
What it does
Elementor’s plugin, renamed Image Optimization in June 2026 but still titled Image Optimizer in the directory, has more than a million installs. It compresses on Elementor’s servers, lossy or lossless, converts to WebP and AVIF, resizes to 1,920 pixels by default and keeps originals, with a restore of every size.
Strengths and limits
For a site built with Elementor, the integration is natural. But it requires an active Elementor account, and its directory rating is the lowest in this comparison, 1.7 out of 5. In October 2026 its listing showed testing up to WordPress 7.0, while 7.1 was out.
Price and audience
The free plan, presented as a trial, covers 200 credits in total, one per optimized file, which is about fifty images with default settings according to the vendor, with 10 MB per image. Paid plans go through the Elementor account and were not displayed publicly. This plugin suits Elementor sites that want an integrated solution, after reading the reviews.
Rewriting, picture tag or CDN: choosing a delivery method
Server-side rewriting
The image URL does not change: the server returns the WebP or AVIF file if the browser accepts it. It is the cleanest method, used by Converter for Media, EWWW, ShortPixel, Imagify or TinyPNG. It requires Apache or LiteSpeed, or hand-written Nginx rules, and can clash with a cache or CDN in front of the site.
The picture tag
The HTML is rewritten to offer several sources, with the JPEG as fallback. It works everywhere, but does not touch CSS background images and can disturb some styles. ShortPixel considers it the least recommended method, while Imagify labels it the preferred option: vendors disagree.
The image CDN
URLs point to a network that picks the format and size for each visitor: Optimole, Jetpack, EWWW’s Easy IO, ShortPixel or Smush. It is the most comfortable option, at the price of a dependency and a quota in visits or bandwidth. The choice of host matters too, as our comparison of WordPress hosting providers shows.
How to choose
- A site that wants a single setting: Imagify, or ShortPixel for several sites.
- Hosting that allows exec() and a zero budget: EWWW, or Converter for Media for WebP only.
- A large existing library: ShortPixel and its lifetime credits.
- No extra files on the server: Optimole or Jetpack Boost’s CDN.
- Staying as close as possible to WordPress: Modern Image Formats, or core’s output filter.
Do not stack two plugins that do the same thing. After optimizing, measure with real-world data, as our guide to Core Web Vitals fixes explains.
Summary table
| Plugin | Model | Modern formats | Originals | Free / entry price (Oct. 2026) |
|---|---|---|---|---|
| Imagify | Online service | WebP, AVIF | Backed up by default | 20 MB a month / $4.99 a month (yearly) |
| ShortPixel | Online service or CDN | WebP, AVIF | Optional backup | 100 credits a month / $10.99 a month |
| EWWW | Server or API | WebP, AVIF via CDN | Replaced only by a lighter file, optional backup | Unlimited locally / $8 a month |
| Smush | Online service or CDN | Pro only | Optional backup | Limited / $50 a year |
| Optimole | CDN | WebP, AVIF | Untouched | 2,000 visits a month / $22.90 a month |
| TinyPNG | Online service | WebP, AVIF | Optional backup | 500 compressions a month / per unit |
| Converter for Media | Server | WebP, AVIF in PRO | Untouched | Free WebP / $5 a month |
| Modern Image Formats | Server | AVIF or WebP | Untouched | Free |
| Jetpack Boost | CDN | WebP | Untouched | Free CDN |
| Image Optimization (Elementor) | Online service | WebP, AVIF | Kept | 200 credits in total (about 50 images) |
Frequently asked questions
Do I still need a plugin with WordPress 7.1?
Often, yes. WordPress 7.1 compresses new images better, but only for uploads made from the block editor, in a recent Chromium browser, over HTTPS. It does not convert to WebP or AVIF without a filter and does not reprocess the existing library.
Should I keep the originals?
Yes, as long as disk space allows. An original lets you recompress with another setting or another tool. Plugins that replace files almost all offer a backup: turn it on before the first bulk run.
AVIF or WebP?
AVIF is generally lighter, and all current major browsers support it, but encoding is slower and not every server can produce it. WebP remains a safe choice. The best plugins offer both, with a fallback.
Can I use several plugins together?
Avoid turning on the same function twice, compression or conversion. Some combinations are intended, such as a file optimizer with Optimole’s CDN, according to its vendor. When in doubt, one tool.
Why does PageSpeed still flag my images?
Since Lighthouse 13, the old image audits are grouped into the “Improve image delivery” insight, which checks compression, formats, animated GIFs and responsive sizing. An image too large for its slot is still flagged, even when compressed.
What happens when I uninstall?
It depends on the tool. Compressed images stay compressed with Imagify. Converter for Media removes its files. With a CDN such as Optimole, URLs simply go back to your original files, unless you offloaded the library to its cloud, a paid option to undo first.
Conclusion
WordPress 7.1 compresses better, but still leaves the question of modern formats to others. Imagify offers the most stress-free default, ShortPixel suits agencies and large libraries, EWWW compresses for free and without limit for those who control their server, Optimole and Jetpack move the problem onto their network.
The 2022 story recalls the essentials: generating a second format, keeping originals or not, choosing a delivery method, these are real choices, with a cost. Read your plugin’s settings, measure before and after, and never hand your whole library to a bulk run without a backup.
Sources
- HTTP Archive (January 15, 2026). Web Almanac 2025, Page Weight
- HTTP Archive (2026). Web Almanac 2025, Performance
- HTTP Archive (December 29, 2024). Web Almanac 2024, Media
- WordPress.org News (August 19, 2026). WordPress 7.1 “Mary Lou”
- Make WordPress Core (July 22, 2026). Client-Side Media Processing in WordPress 7.1
- Make WordPress Core, Adam Silverstein (February 23, 2024). WordPress 6.5 adds AVIF support
- Make WordPress Core (June 7, 2021). WordPress 5.8 adds WebP support
- Make WordPress Core (October 9, 2019). Introducing handling of big images in WordPress 5.3
- Make WordPress Core (November 10, 2015). Responsive Images in WordPress 4.4
- Make WordPress Core, Adam Silverstein (March 28, 2022). Enabling WebP by default
- Make WordPress Core, Adam Silverstein (April 12, 2022). Follow-up on WebP by default proposal
- Make WordPress Core, Adam Silverstein (June 30, 2022). Plan for adding WebP & multiple MIME support for images
- Make WordPress Core, Matt Mullenweg (September 11, 2022). WebP in Core for 6.1
- GitHub, wordpress-develop (September 19, 2022). Media: Revert WebP generation
- WP Tavern, Sarah Gooding (August 24, 2022). WebP by Default on Hold for 6.1 After New Objections From WordPress Lead Developers
- WP Tavern, Sarah Gooding (September 20, 2022). WebP by Default Pulled from Upcoming WordPress 6.1 Release
- Chrome for Developers (October 2025). Improve image delivery insight
- web.dev. Learn Images: JPEG
- WordPress.org (October 2026). Imagify
- Imagify (October 2026). Pricing
- WordPress.org (October 2026). ShortPixel Image Optimizer
- ShortPixel (October 2026). Plans & Pricing
- ShortPixel. Which WebP files delivery method is the best for me?
- WordPress.org (October 2026). EWWW Image Optimizer
- EWWW.io (October 2026). Plans
- EWWW.io. WebP delivery
- WordPress.org (October 2026). Smush
- WPMU DEV (October 2026). Smush Pro
- WordPress.org (October 2026). Optimole
- Optimole (October 2026). Pricing
- WordPress.org (October 2026). TinyPNG, JPEG, PNG & WebP image compression
- Tinify (October 2026). Developer API pricing
- WordPress.org (October 2026). Converter for Media
- matt plugins (October 2026). Converter for Media PRO
- WordPress.org (October 2026). Modern Image Formats
- WordPress.org (October 2026). Jetpack Boost
- Jetpack. Site Accelerator
- WordPress.org (October 2026). Image Optimization by Elementor
- Elementor (October 2026). Image Optimizer
- Chrome for Developers. Serve images in modern formats
- GitHub, wordpress-develop (7.1 branch). src/wp-includes/media.php
- GitHub, wordpress-develop (September 6, 2022). Media: Output WebP by default when uploading JPEGs
- Make WordPress Core (August 15, 2024). Automatic conversion of HEIC images to JPEG in WordPress 6.7
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