Which WordPress Image Optimization Plugin Do You Need?

Most WordPress image optimization plugins do one of two different jobs. A compressor rewrites the image files in your media library once, when you upload them. An image CDN leaves those files alone and hands each visitor a lighter copy, every time the image is requested.

Almost everything that matters follows from that split: what the plugin charges for, what happens to your originals, and what is left when you stop paying. So this page starts there and names products second.

One disclosure before the first table: NimboCDN is mine, and it is one of the rows. Every claim about the other five links to their own website or WordPress.org listing, checked on September 15, 2026.

Compressor or image CDN: which kind of plugin do you need?

An image compressor makes the files stored in your WordPress media library smaller — once, at upload or in a bulk pass — and your hosting keeps delivering them. An image CDN keeps your files exactly as they are and delivers a resized, converted copy to each visitor from its own servers. The first changes your files. The second changes how they travel.

Neither kind wins in the abstract. A compressor costs nothing per visit because it is not there when the visit happens; the price is that every visitor gets the same file, decided the day you uploaded it. A CDN decides at the moment of the request — AVIF for a browser that takes it, a narrower width for a phone — and the price is depending on someone else’s servers, usually with a meter attached.

And both start from a baseline most comparisons skip: what WordPress does on its own.

What WordPress already does before you install anything

A default WordPress install already does four of the things image plugins advertise, according to its own developer documentation:

• It makes several sizes of every upload. Since version 4.4, WordPress automatically creates several sizes of each image uploaded to the media library and lists them in a srcset attribute, so the browser downloads the one that fits (WordPress core notes).
• It scales down oversized originals. If the original image width or height is above the threshold, it will be scaled down — and that threshold defaults to 2,560 pixels (developer reference).
• It lazy-loads. Since 5.5, images below the fold wait until the reader scrolls, using the browser’s native loading attribute (core notes).
• It accepts WebP and AVIF. WebP uploads since 5.8 and AVIF since 6.5 — in both cases only if your hosting’s image library supports the format (AVIF notes).

What it does not do is turn your JPEGs into WebP or AVIF. Accepting a format is not converting to it. For that, the WordPress Performance Team publishes a free plugin, Modern Image Formats, with more than 100,000 active installations. Its listing describes the default plainly:

By default, AVIF images will be generated if supported on the hosting server, otherwise WebP will be used as the output format.

Two limits come with it: it works on new uploads, and existing images only change format if you regenerate them. Both are on the same listing.

Does the gap show on real sites? In our own study of 41 storefronts across 14 platforms, the median share of images already in a modern format was 0% on the 3 WordPress sites, 48% on the 4 WooCommerce stores and 100% on the 12 Shopify stores. Three sites are not a census, and we say so. But it matches what the documentation predicts: WordPress will take a WebP if you hand it one. It won’t make one for you.

If your images are already reasonably sized and WebP is not on your list, WordPress on its own may be enough. It costs nothing, and it is the baseline every plugin below should beat.

What each plugin charges for

The six tools on this page do not charge for the same thing, so a cheapest-first ranking would compare unlike units. The honest comparison is what runs out:

Tool	Charges by	What runs out
ImagifyCompressor, no CDN	MB of images / month	20 MB free · 500 MB for $5.99/mo · unlimited for $11.99/mo
ShortPixel Image OptimizerCompressor	credits	100 free credits a month · unlimited for $9.99/mo · one-off packs from $19.99
EWWW Image OptimizerCompressor with a paid CDN	GB of CDN bandwidth	Nothing in local mode · Easy IO CDN: 50, 200 or 400 GB from $8/mo
SmushCompressor with a paid CDN	number of sites	1, 3 or 10 sites for $50–$100/yr · unlimited for $9.99/mo
OptimoleImage CDN	visits / month	2,000 free · 48,000 · 120,000 · 300,000 by plan
NimboCDNoursImage CDN	flat rate	No traffic meter · the free plan covers your home page, 50 new images a month

Prices are each vendor’s own list prices in US dollars, monthly where they sell monthly. Smush’s single-site to ten-site plans are sold per year. Its unlimited Premium tier is listed at $9.99 a month and currently shown at $4.99 for the first three months; the table uses the list price.

Read the right-hand column against your own site. A photo-heavy blog with modest traffic burns through megabytes and never touches a visit ceiling. A store with a dozen product shots and a lot of visitors is the reverse. Same plugins, opposite fit.

Does the plugin touch your original images?

This is the question that decides whether a bad setting can be undone, and each vendor answers it differently:

A backup turns a one-way decision into a reversible one, at the cost of disk space. ShortPixel even added Smart Backups: Save disk space by backing up only the main image. That is a fair trade, not a flaw. What matters is knowing which default you get before the first bulk run, not after it.

What happens when you run out, or stop paying?

A compressor’s work is already written into your media library, so the files it compressed stay compressed. With an image CDN the answer depends on the vendor, and these three document it:

• Optimole. On the free plan, go over the limit without upgrading and its documentation says Optimole will return your original images and permanently deactivate your account's optimized image delivery. On paid plans it goes the other way: Optimole will notify you by email and will automatically upgrade your subscription to the next plan tier — and Automatic quota upgrades for premium plans cannot be disabled (Optimole docs).
• ShortPixel Adaptive Images, ShortPixel’s separate CDN plugin: When the quota is exhausted, the plugin will simply serve the original images from your server, without compression or resizing, until the quota resets (its listing).
• NimboCDN. A failed payment does not drop the plan that day: there are three days of grace, then the site returns to the free plan. The home page stays optimized and the rest of the site is served from your server, exactly as before.

If Optimole is the plugin you already run, our breakdown of each Optimole alternative and what it charges goes through its visit tiers and how to leave them without breaking anything.

Where these facts come from

Every claim about another product was read on the vendor’s own website, its WordPress.org listing or the WordPress.org plugin API on September 15, 2026, and each one is cited at the foot of this page. Installation counts and ratings come from that API. None of it comes from a review or a comparison site.

One vendor could not be read that way: Optimole paints its prices with JavaScript, so those figures were observed on its pricing page on August 31, 2026 and checked again on September 9.

Three things this page deliberately does not do:

• It does not test compression quality. Some comparisons run a sample image through each plugin; this one does not. Our own measured figures are about formats — AVIF against JPEG at equal perceived quality — not about any single plugin.
• It leaves out performance suites. Jetpack Boost, WP-Optimize, NitroPack and Elementor’s Image Optimizer fold image features into broader products. They deserve a comparison of their own.
• It does not promise speed. We report image bytes. Page-load time also depends on your hosting, your theme and everything else on the page.

Imagify

Who it is for. Sites that already have a CDN, or do not need one, and want modern formats without a subscription.

Imagify is a compressor: it shrinks your files and leaves them on your server, with no delivery network of its own. On its pricing page, the free Starter plan covers 20 MB a month — about 200 images, with a 2 MB limit per image. Growth is $5.99 a month for 500 MB, plus $5 per additional GB. Infinite is $11.99 for unlimited images. All three allow unlimited websites.

Two facts decide it. The good one is on its WordPress.org listing: WebP and AVIF conversion included in the free plan. The one to decide on purpose is the originals table above: by default, Imagify replaces them.

Verdict. Pick it if you want AVIF for free and you will set up the backup first. Skip it if you would rather nothing rewrote your library.

ShortPixel Image Optimizer

Who it is for. Anyone who wants compression with a safety net, and agencies that would rather buy credits once than carry another subscription.

ShortPixel makes two different plugins, and it pays to tell them apart. Image Optimizer, the one here, compresses the files in your library and, per its listing, says original images are backed up locally, restorable one by one or in bulk. Adaptive Images is its separate CDN plugin, which leaves your files alone.

Pricing is in credits, and the listing puts it in one sentence: ShortPixel comes with 100 free credits per month, and additional unlimited monthly credits can be purchased for $9.99. One-time credit packages that never expire are available starting at $19.99.

Verdict. Pick it if you want compression you can undo. Skip it if you want size and format decided per visitor: even at ShortPixel, that is a different plugin.

EWWW Image Optimizer

Who it is for. Anyone who wants to optimize without sending a single file to anybody’s cloud.

EWWW is, in its own words, the only plugin that lets you optimize images using tools on your own web server (jpegtran, optipng, pngout, pngquant, gifsicle, cwebp). That local mode is free and unmetered — its listing offers Unlimited image optimization to compress images of any size, with local backups. It needs the PHP exec() function; on hosts without it, EWWW offers free lossless JPG compression and WebP conversion through its Compress API.

The paid side is Easy IO, a CDN billed by bandwidth. On its plans page: $8, $16 or $32 a month — $80, $160 or $320 a year — for 50, 200 or 400 GB, with unlimited images and sites, and extra bandwidth on the top plan at $0.065 per GB. AVIF lives there too: AVIF conversion is built into the Easy IO CDN.

Verdict. Pick it if your real objection is the dependency: in local mode nothing leaves your server and nothing is metered. Skip it if you want AVIF without paying.

Smush

Who it is for. Agencies with a known roster of sites. It is the only tool here that charges per site.

The free Smush compresses on upload and in bulk, and its listing is explicit about originals: Smush does not delete your original images. It compresses and optimizes resized versions by default. Full-size image compression is available in Smush Pro. The free version also has a hard edge: In the free version, images over 5MB are skipped.

Pro is sold per site: $50 a year for one, $75 for three, $100 for ten, each with 50 GB of CDN on a network described as Global CDN (119 nodes), without naming the operator. Unlimited sites is the Premium tier, listed at $9.99 a month. Serving WebP and AVIF is marked Pro on the listing.

Verdict. Pick it if you need to know today what next year’s bill will be. Skip it if you want modern formats without paying: in Smush they are Pro.

Optimole

Who it is for. A large library, predictable traffic and no appetite for configuring anything.

Optimole is an image CDN by design. It delivers optimized copies from its network and works without altering the original files on your server. It bills by visits, which its pricing page defines this way: Each visitor is counted as a unique daily user, regardless of their actions or return frequency within 24 hours.

The free plan is on its WordPress.org listing: Free plan with all features – For sites with up to 2000 visits /month, or 22,000 while its badge shows on your site. Paid plans with monthly billing are Starter at $22.90 for 48,000 visits, Business at $47.00 for 120,000 and Flexible at $109.00 for 300,000.

Verdict. Pick it if your traffic is predictable and your library is large. Skip it if your visits spike: that is exactly where the meter sits.

NimboCDN

Saying it plainly one more time: this one is mine. Read it with that in mind, and check it against the five above.

Who it is for. A WordPress store that wants the CDN model — size and format decided per visitor — without a meter on traffic.

$9.90 a month, or $99 a year. Flat rate. Each image is transformed once and then served from cache. Once it is cached, no request reaches the transformation service — we measured that, and it is why visits are not what we count.

The connector never touches your originals: nothing is recompressed, moved or deleted, and switching it off serves your own images again at once. If the service stops answering, your site serves its own images; we tested origin down, origin slow, a corrupt file and an invalid signature, and all four end on the original image.

On format, at equal perceived quality (SSIMULACRA2 at 70), AVIF came out 32.1% lighter than JPEG at the median, across 14 images from two real stores. Those are image bytes. We did not measure page-load time, which also depends on your hosting and theme.

The free plan is a sample, not a usage tier. It covers your home page, up to 50 new images a month, in WebP. The whole site and AVIF come with the paid plan.

Verdict. Pick it if you want per-visitor delivery with a bill that does not move with traffic. Skip it if what you are buying is track record: the connector is new, and the others have years of it.

Which WordPress image optimization plugin should you choose?

Side by side, what each one delivers:

• Small site, images already sized sensibly. Start with WordPress on its own, and add Modern Image Formats if you want WebP or AVIF on new uploads.
• You want nothing to leave your server. EWWW in local mode: free, unmetered, with local backups.
• You want AVIF and do not want to pay. Imagify — switch the backup on before the first bulk run.
• You want to be able to undo it. ShortPixel Image Optimizer, which backs your originals up locally.
• You manage a fixed set of client sites. Smush, priced per site.
• You want size and format decided per visitor. An image CDN: Optimole if your traffic is steady and your library large, NimboCDN if you would rather have no traffic meter at all.
• You are not sure yet. Weigh what your pages serve today with the image size checker before you pay anyone.

Frequently asked questions

Do I need an image optimization plugin for WordPress at all?

Not always. WordPress already creates several sizes of each upload, lists them in srcset, scales down anything over 2,560 pixels and lazy-loads images. A plugin earns its place when you want smaller files than that, WebP or AVIF without converting by hand, or images delivered from a CDN instead of your hosting.

What is the difference between an image compressor and an image CDN?

A compressor makes the files in your media library smaller once, at upload or in a bulk pass, and your hosting keeps delivering them. An image CDN leaves your files as they are and delivers a resized, converted copy from its own servers each time a page requests the image. One changes the files; the other changes the delivery.

Which image optimization plugins keep my original files?

Optimole and NimboCDN leave your originals on your server untouched. Smush states that it does not delete originals and compresses the resized versions by default. ShortPixel Image Optimizer backs originals up locally, and EWWW offers local backups. Imagify replaces originals with the optimized versions unless you enable its backup.

Does WordPress convert images to WebP or AVIF by itself?

No. WordPress accepts WebP uploads since version 5.8 and AVIF since 6.5, if your hosting’s image library supports them, but it does not convert JPEG or PNG uploads. The free Modern Image Formats plugin from the WordPress Performance Team does, for new uploads; existing images change format only if you regenerate them.

Will an image optimization plugin improve my Google ranking?

No plugin can promise a position. Google takes page speed into account, and images are often what decides LCP, one of the metrics it measures. Google has also indexed AVIF since 2024 with nothing special required. What a plugin measurably changes is how many bytes your images weigh, and that is what we report.

Is there a WordPress image optimization plugin with no traffic limit?

Several, each in its own way. EWWW’s local mode has no meter at all, and Imagify’s Infinite plan and ShortPixel’s unlimited monthly credits do not count visits. Among image CDNs, NimboCDN charges a flat rate and never counts traffic, while Optimole bills by visits and the Pro plans of Smush cap CDN traffic at 50 GB.