WebberZone Image Optimizer

WebberZone Image Optimizer converts the images already in your media library to WebP and AVIF, and serves each visitor the smallest file their browser can read. Images are typically 40–60% smaller with no visible difference.

Everything happens on your own server. Your images are never uploaded anywhere. The plugin makes no outbound network requests of any kind — there is no external service, no API key, no monthly image quota, no account to create and nothing that can stop working because a company shut down or changed its pricing.

What your server needs

Almost certainly nothing you do not already have. WordPress cannot crop or resize an uploaded image without either the Imagick or the GD extension, so every working WordPress install already has one of them, and both have been able to write WebP for years.

• WebP works on virtually any current host. GD has supported it since PHP 5.5, Imagick since well before that.
• AVIF is newer and less universal. It needs either PHP 8.1+ with GD built against libavif, or Imagick with an AVIF delegate. Plenty of hosts have it; plenty do not yet.

You do not have to guess. The plugin tests your server by actually encoding a small image with each backend at activation, rather than trusting what the extension claims to support, and the settings screen shows you exactly which formats came back working. If AVIF is unavailable the option is simply marked as such and WebP carries on normally.

Your originals are never modified

By default, each optimized copy is written alongside the original with the new extension appended, so photo.jpg gains photo.jpg.webp. The File naming setting can switch this to replacing the extension instead (photo.webp) — see the settings screen for the trade-off before turning it on. Either way, nothing overwrites, replaces or re-saves your original file. Deactivating the plugin returns your site to serving the originals immediately, and no URL ever breaks.

Delivery that survives caching

Images are wrapped in a <picture> element, so the browser chooses the format. That matters more than it sounds: the common alternative is to vary the response on the Accept header, which returns different bytes for a single URL. Any cache in front of that — a page cache plugin, a CDN — which ignores Vary will happily hand a WebP file to a browser that cannot display it. A <picture> element has no such failure mode.

Responsive images are handled properly. Every candidate in an image’s srcset is mapped to its optimized copy, with the width descriptors preserved exactly. If even one size in the set is missing, the whole image falls back to the original rather than letting the browser request a file that does not exist.

For images referenced from a stylesheet, where the browser is never offered a choice, the Delivery tab generates ready-to-paste Apache and nginx rules, complete with the Vary: Accept header those rules require.

Bulk conversion that finishes

The bulk screen works through a database-backed queue one batch at a time. Close the tab and nothing is lost; a background worker carries on, and reopening the screen resumes exactly where it stopped. Failures are retried a few times and then listed with the reason.

Features

• WebP and AVIF, generated together or separately (AVIF where the server supports it)
• Bulk conversion of an existing media library, resumable and interruptible
• Automatic conversion of new uploads
• Lazy conversion: an image seen on the front end but not yet converted is queued, never encoded during the page render
• Per-format quality, encoder effort, and lossless mode for PNG sources
• An optimized copy that comes out no smaller than its source is discarded, per file
• Metadata stripped from the copies while the colour profile is kept, so colours do not shift
• Animated GIFs keep their animation when ImageMagick is available
• Memory guard that skips an image rather than crashing a batch
• Per-image status and actions in the Media library
• Multisite aware: per-site queues, tables created for new sites automatically
• WP-CLI: wp wzio status, convert, queue, run, clean
• Filters throughout for developers