About this plugin
EmergentPixel Image Optimizer replaces the handful of image plugins most sites run with one modular plugin. Everything runs on your own server: your images never leave it, there are no credits, no monthly limits and no API keys.
Compression
- Lossless, Smart (recommended) and Lossy levels, using Imagick when available and GD everywhere else.
- New uploads are compressed in the background; a bulk optimizer handles your existing library, even when you close the browser.
- Originals are backed up first. Restore any image with one click, or re-optimize it at another level.
- Camera data and GPS location are removed, colour profiles are kept.
WebP and AVIF
- A WebP copy of every image and size, kept only when it is smaller. Optional AVIF copies too, usually even smaller, served with <picture> tags, rewrite rules or the Nginx snippet.
- Served by default as plain <img> tags whose src and srcset point at the.webp files, on any server, page cache and CDN, including images your theme or ACF fields output. Choose <picture> tags if you also want a JPEG fallback for very old browsers. Rewrite rules (Apache, LiteSpeed) and a ready-made Nginx snippet are available too. A “Test delivery” button checks that it works.
- Or turn on “Convert to WebP”: uploads become real WebP files in the Media Library, existing images can be converted in the background with links updated, and originals are kept in a backup folder.
Faster pages (Core Web Vitals)
- Lazy loading for images and iframes with plain HTML attributes. No JavaScript is added to your site.
- The first images and the featured image load right away; the main image gets fetchpriority="high" (LCP).
- Missing width and height are added to stop layout shift (CLS).
- Optional YouTube and Vimeo previews that load the player only on click.
Media tools
- Thumbnail manager: see every image size, who added it and how much space it uses; turn off sizes you do not need; regenerate all or only missing thumbnails.
- Alt text editor: see which images have no alt text, edit alt text for every image in one list, and fill missing alt text in bulk from the image title, the file name or the page the image belongs to. Alt text you wrote is never changed, and camera names like “IMG_2034” are skipped.
- Upload rules: resize huge uploads, clean file names (“IMG_2034 Final (1).JPG” becomes “image-2034.jpg”), add alt text from the file name.
- Safe SVG uploads for the roles you choose; every file is sanitized.
- Replace media: upload a new version and keep the same URL, or use the new name and update links.
- Attachment pages redirect to the post the image belongs to.
Every feature is a module you can switch off. A switched-off module adds no code to your site.
Pro (planned)
A Pro add-on is planned. It will add blur placeholders, CSS background-image lazy loading, media cleanup and more. The free plugin is complete on its own and will never be limited.
External services
The plugin does not connect to any service by default.
YouTube thumbnails (optional). When you turn on “YouTube and Vimeo preview” in Performance, YouTube videos that are already embedded in your content show a preview image until the visitor clicks play. jpg ); this sends the visitor’s IP address and the video ID to YouTube.
Nothing loads from YouTube or Vimeo before that, so this replaces the full player that would otherwise load on every page view. YouTube is provided by Google: Terms of Service, Privacy Policy.
Source code
The admin screens are built with @wordpress/scripts. The readable source is included in the plugin under assets/src/. To rebuild assets/build/, run npm install and npm run build in the plugin folder.
Third-party libraries
- Action Scheduler (GPL-3.0-or-later) by Automattic — background processing. https://actionscheduler.org/
- svg-sanitizer (GPL-2.0-or-later) by Daryll Doyle — SVG cleaning, bundled under the EPIM\Vendor namespace. https://github.com/darylldoyle/svg-sanitizer