EWWW Image Optimizer
Image optimizer that compresses images on your own server for free with unlimited WebP, plus paid cloud compression and the Easy IO…
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ShortPixel Image Optimizer
Credit-based cloud image optimizer with lossy, glossy and lossless modes, free WebP/AVIF, PDF compression and an optional CDN.
Free installs300K+WordPress.org, active
Est. Pro installs~52KLikely 26K–100K
Vendor claims1M+Vendor's own figure
Rating4.5/5830 reviews
Price from$9.99/moFreemium
Last updated14 Oct 2026Version 6.6.1
Overview
ShortPixel Image Optimizer (often shortened to SPIO) is a cloud-based optimizer that sends images, thumbnails and PDFs to ShortPixel’s servers and replaces them with smaller versions. It has been around since 2014 and is known for a deep set of settings rather than a minimal interface.
Unlike most rivals, ShortPixel does not split features into free and Pro. Every installation gets the same toolset; what you pay for is credits. One credit is used for each image or thumbnail that is reduced by at least 5%, and the free account receives 100 credits a month. Because a single upload usually produces several thumbnails, the free allowance only covers a handful of uploads, so most real sites end up on a paid plan.
Main capabilities
- Lossy, glossy (a high-quality lossy mode) and lossless compression for JPG, PNG, GIF and PDF.
- WebP and AVIF creation, delivered with picture tags, .htaccess rules or ShortPixel’s CDN.
- Resizing of large images, EXIF control, PNG-to-JPG conversion and CMYK-to-RGB conversion.
- Local backups with one-click restore, plus per-thumbnail exclusions and regex exclusion rules.
- Optimization of custom folders, NextGEN and other gallery plugins, WooCommerce images and multisite networks.
- Newer AI tools such as alt text generation, smart cropping, upscaling and background removal.
Pricing is simple: an Unlimited plan at $9.99 per month (or $99.90 per year) removes the credit cap and includes 500GB of CDN traffic, while one-time credit packs from $19.99 never expire and suit sites that only need an initial bulk run. Credits can be shared across several sites with one API key.
Limitations: the free tier is very small, there is no local processing option, and lazy loading and on-the-fly responsive resizing live in the separate ShortPixel Adaptive Images plugin. CDN delivery on the main plugin consumes credits unless you are on the Unlimited plan.
Who should pick it: owners of image-heavy sites, photographers and agencies who want fine control over compression and formats, and are happy to pay a small monthly fee or buy a one-off credit pack.
Best for: Image-heavy sites and agencies that want granular compression and format control and are willing to pay for credits or the Unlimited plan.
ShortPixel offers one of the most complete feature sets in the category, and nothing is locked behind a Pro edition. The trade-off is the tiny free quota, so treat it as a low-cost paid service rather than a free plugin. The $9.99 Unlimited plan is good value for multi-site owners.
Pros
- Lossy, glossy and lossless modes give fine control over quality
- WebP and AVIF included for every account, with three delivery methods
- Compresses PDFs and converts PNG to JPG
- Optimizes custom folders, gallery plugins and WooCommerce images
- Cheap Unlimited plan and non-expiring one-time credit packs
- Works offloaded on ShortPixel's cloud, so hosting CPU is spared
Cons
- Free allowance of 100 credits/month runs out after a few uploads
- Every thumbnail consumes a credit
- No local processing option
- Lazy load and adaptive resizing require the separate Adaptive Images plugin
- Large number of settings can overwhelm beginners
Key features
What ShortPixel Image Optimizer highlights on its WordPress.org page and its own website, split by version.
Free version WordPress.org
- 100 free credits every month
- Lossy, glossy and lossless compression
- WebP and AVIF conversion
- PDF and animated GIF optimization
- Bulk optimization in background mode
- Resize large images on upload
- Local backups with one-click restore
- Per-thumbnail and regex exclusions
- Custom folder optimization
- NextGEN, WooCommerce and WPML compatible
- Multisite with a single API key
- WP-CLI support
- AI alt text and smart cropping
Pro / paid adds From $9.99/mo
- Unlimited credits for $9.99/month
- 500GB monthly CDN traffic included
- Non-expiring one-time credit packs
- Credits shared across multiple sites
- CDN delivery for images, CSS and fonts
- Cloudflare integration via API token
- API key aliases for agencies
- Credits usable in Adaptive Images plugin
Feature checklist
23 of 25 features we track in Image Optimization, feature score 90/100
Compression 7/7
Lossy & lossless compression Key
Choose between lossless and one or more lossy compression levels.
Choose lossy, glossy or lossless compression.
Included
Bulk optimisation Key
Optimise every existing image in the media library.
One-click bulk optimization with background mode; uses credits.
Included
Optimise on upload
New uploads are optimised automatically.
New uploads and their thumbnails are optimized automatically.
Included
Keep & restore originals Key
Backs up originals so you can restore them.
Local backups with one-click restore; optional smart backups of main image only.
Included
Resize large images
Scales down oversized uploads to a maximum size.
Scales down large images to set maximum dimensions.
Included
Strip EXIF metadata
Removes camera and location metadata.
EXIF can be kept or removed.
Included
PDF compression
Compresses PDF files in the media library.
Compresses PDF documents as well as images.
Included
Next-gen formats 4/4
WebP conversion Key
Creates WebP versions of images.
Creates WebP versions; available to all accounts.
Included
AVIF conversion Key
Creates AVIF versions of images.
Creates AVIF versions; available to all accounts.
Included
Automatic next-gen delivery
Serves WebP/AVIF to supporting browsers via picture tags, rewrites or CDN.
Delivers WebP/AVIF via picture tags, .htaccess rules or the CDN.
Included
PNG to JPG conversion
Converts photos saved as PNG to smaller JPGs.
Optional automatic PNG-to-JPG conversion when the result is smaller.
Included
Delivery 4/4
Image CDN Key
Serves images from a CDN, often with on-the-fly optimisation.
Built-in CDN delivery; traffic uses credits unless on Unlimited (500GB/month).
Paid version Unlimited
Adaptive image sizes
Serves the right size for each screen or device.
Free ShortPixel Adaptive Images plugin serves viewport-sized images via CDN (uses credits).
Via add-on
Lazy loading
Defers off-screen images.
Provided by the free ShortPixel Adaptive Images companion plugin.
Via add-on
CSS background images
Also optimises or converts images used in CSS backgrounds.
CSS background images can be served from the CDN option, which consumes credits.
Partial
Processing & limits 3/5
Local processing
Optimises on your own server with no external API.
All optimization runs in ShortPixel's cloud.
Not included
Cloud processing
Optimisation runs on the vendor's servers, saving your server's CPU.
Optimization runs on ShortPixel's servers, sparing hosting resources.
Included
Generous free tier
Free version optimises unlimited images, or a large monthly quota.
Only 100 credits per month, and each thumbnail counts as a credit.
Not included
No small file-size cap
No restrictive per-image size limit in the free version.
Per-image limit is 100MB, which is not restrictive for normal use.
Included
Thumbnail control
Choose which thumbnail sizes are optimised.
Exclude individual thumbnail sizes from optimization.
Included
Extras & compatibility 5/5
Optimise other folders
Optimise theme, plugin or custom folders outside the media library.
Other Media lets you add custom folders to optimize.
Included
WooCommerce & gallery plugins
Optimises WooCommerce product and gallery-plugin images.
Compatible with WooCommerce, NextGEN, Modula, FooGallery and others.
Included
Multisite support
Works across a WordPress multisite network.
Works on multisite networks with a single API key.
Included
WP-CLI
Run bulk optimisation from the command line.
WP-CLI commands for background and scheduled processing.
Included
Savings reports
Shows space saved and optimisation statistics.
Shows savings and a 30-day optimization report.
Included
Pricing
Free
$0On WordPress.org
Free
Freeper monthMultiple
100 credits per month; each image or thumbnail optimized uses one credit.
Unlimited (monthly)
$9.99per monthMultiple
Unlimited optimization credits and 500GB CDN traffic per month.
Unlimited (annual)
$99.90per yearMultiple
Annual billing of the Unlimited plan (two months free).
One-time credits
$19.99one-offMultiple
Entry price for one-time credit packages; credits never expire and can be stacked.
Prices are list prices from the vendor's site, checked 14 Oct 2026. Many vendors discount the first year.
How many sites use ShortPixel Image Optimizer?
Free installs from WordPress.org, the vendor's own claim, and our estimate of paid installs.
Free version (WordPress.org)
300K+
Active installations reported by WordPress.org.
Vendor claim
1M+
Sites/users claimed on the vendor's website. source
Estimated Pro / paid installs
~52K
Our estimate, see method below.
How we estimated this: About 350K free installs x 12% (the usual share of free sites that also run the paid version when a hosted service whose free tier is limited) gives 42K. The vendor claims 1M+ sites in total. Taking away about 350K free installs leaves 650K, and 80% of that is 520K. Vendor totals are loose, so we only move our figure part of the way toward it, from 42K to 52K. Likely range: 26K to 100K. This counts sites running the paid version, including sites whose licence has lapsed. Estimates are rough and based on public figures as of 14 Oct 2026.
Stats & health
Weekly downloads
32,557 downloads last week, 20.4M all time
Rating breakdown
| Version | 6.6.1 |
|---|---|
| Last updated | 14 Oct 2026 (19 days ago) |
| Tested up to | WordPress 7.1.4 |
| Requires | WordPress 5.9.0+, PHP 7.4+ |
| Support threads (2 months) | 2 of 2 resolved |
| On WordPress.org since | 5 Nov 2014 |
Company & policy
| Paying customers claimed | 600K users (source, 6 Oct 2026) Homepage claims 600,000 users worldwide (all products, free and paid). |
|---|---|
| Founded | 2014 (source, 6 Oct 2026) Site footer copyright starts in 2014. |
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FAQ
Is ShortPixel Image Optimizer free?
Yes. ShortPixel Image Optimizer has a free version on WordPress.org. Paid plans start at $9.99/mo.
How many sites use ShortPixel Image Optimizer?
WordPress.org reports 300K+ active installations of the free version. The vendor claims 1M+ sites in total. We estimate around 52K sites run the paid version.
Does ShortPixel Image Optimizer have lossy & lossless compression?
Yes: included. Choose lossy, glossy or lossless compression.
Does ShortPixel Image Optimizer have bulk optimisation?
Yes: included. One-click bulk optimization with background mode; uses credits.
Does ShortPixel Image Optimizer have keep & restore originals?
Yes: included. Local backups with one-click restore; optional smart backups of main image only.
Does ShortPixel Image Optimizer have webp conversion?
Yes: included. Creates WebP versions; available to all accounts.
Does ShortPixel Image Optimizer have avif conversion?
Yes: included. Creates AVIF versions; available to all accounts.
Does ShortPixel Image Optimizer have image cdn?
Yes: paid version (Unlimited). Built-in CDN delivery; traffic uses credits unless on Unlimited (500GB/month).
Is ShortPixel free?
The plugin is free and fully featured, but optimization uses credits. Free accounts get 100 credits a month, and each image or thumbnail that is optimized uses one credit.
How much does ShortPixel cost?
The Unlimited plan is $9.99 per month or $99.90 per year and includes 500GB of CDN traffic. One-time credit packages start at $19.99 and never expire.
Does ShortPixel include lazy loading?
Lazy loading and on-the-fly responsive resizing are handled by the separate ShortPixel Adaptive Images plugin, which can use the same account credits.
Can I use one ShortPixel account on several sites?
Yes. Credits are tied to your API key and can be shared across multiple sites, including multisite networks.
Last updated 6 Oct 2026. Spotted something wrong? Suggest an edit.