WebberZone Image Optimizer – WebP & AVIF Converter, Compress Images

WebberZone Image Optimizer is a free WebP converter and AVIF converter for WordPress. It converts the JPEG, PNG, GIF and WebP images already in your media library to WebP and AVIF, optimizes new uploads automatically, and serves each visitor the smallest file their browser can read. Images are typically 40–60% smaller with no visible difference, so pages load faster and score better on PageSpeed Insights and Core Web Vitals.

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. AVIF is not a paid upgrade: every feature is free.

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.

Compress and resize JPEG and PNG originals

By default, each optimized copy is written alongside the original with the new extension appended, so photo.jpg gains photo.jpg.webp, and the original is left unchanged. 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.

You can also compress the original JPEG and PNG files themselves. JPEG compression uses Imagick or GD at the quality you choose; PNG compression uses a local oxipng or pngquant tool when your server has one. A maximum image dimension resizes oversized uploads and, optionally, existing originals. Every change is backed up first, and Restore originals reverses it. Both features are off by default. Deactivation stops optimized delivery but does not restore compressed originals.

Serve WebP and AVIF with the picture element, safe behind caches and CDNs

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. Each format’s <source> lists only the optimized srcset candidates that exist, with their descriptors preserved exactly. Missing intermediate copies are omitted, while a missing smallest, widest or highest-density copy withholds that format so the optimized set always covers the same range as the original set. The original <img> remains as the fallback.

Background images set in block styles, such as Group and Cover block backgrounds, get a CSS image-set() alternative, which does the same job as <picture> in CSS. For images referenced from a stylesheet file, 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 optimize your existing media library

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

• Convert JPEG, PNG and GIF to WebP and AVIF, together or separately (AVIF where the server supports it), and WebP uploads to AVIF
• Bulk conversion of an existing media library, resumable and interruptible
• Automatic conversion of new uploads
• Optional JPEG and PNG compression of the originals, with backups and Restore originals
• Maximum image dimension to resize oversized uploads
• Reuses WebP and AVIF files already created by another image optimizer instead of converting again
• 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
• A lossy optimized copy that misses the minimum saving is retried once at a lower quality before being discarded, per file
• Metadata stripped from the copies while the color profile is kept, so colors 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, with a filter for optimized, not-yet-optimized, skipped and failed images
• Bulk Optimize warns when images are queued but the background worker has stopped running, and gives the commands that recover it
• WebP and AVIF for background images set in block styles, using CSS image-set()
• Site Health tests and an Info section covering encoders, the queue and delivery settings
• Abilities API support on WordPress 6.9+, so AI assistants and MCP clients can check status, run Bulk Optimize and change settings
• Multisite aware: per-site queues, tables created for new sites automatically
• WP-CLI: wp wzio status, convert, queue, run, clean
• Filters throughout for developers