DZIEWA Media Converter — AVIF + WebP

DZIEWA Media Converter creates sidecar .avif and .webp files next to your originals (no replacement of JPG/PNG in the Media Library). On the front end it can rewrite <img> tags to <picture> so browsers pick AVIF/WebP when available. The plugin is entirely free to use — no license fees, no pro version, and no paid add-ons.

How it works

The plugin generates additional AVIF and/or WebP files beside every JPEG/PNG you upload. Originals are never touched or replaced — they remain in the Media Library and on disk as a safe fallback. The optional content filter detects <img> tags in your post content and wraps them in <picture> so modern browsers download the smaller AVIF/WebP version, while older browsers transparently fall back to JPG/PNG.

Conversion

• AVIF + WebP, AVIF-only or WebP-only output modes. AVIF requires PHP GD built with AVIF support; the plugin auto-detects this on activation and gracefully falls back to WebP-only when AVIF is unavailable.
• Configurable quality per format (independent AVIF and WebP quality sliders in settings).
• Automatic conversion on upload — new attachments are converted in the background via WP-Cron or Action Scheduler (when available), so the upload screen never blocks.
• Intermediate sizes (thumbnails) are optionally converted too, so every srcset variant has its own AVIF/WebP sidecar.

Existing media

• Background queue processes already-uploaded images in configurable batches (default 20 files per run, range 5–200). You can scope the queue to a single uploads subfolder and/or a date range to avoid scanning the whole library at once.
• Bulk action in the Media Library — select images and run Convert to AVIF/WebP from the bulk menu.
• Per-attachment button — Media Library list, attachment edit screen and media modal each show a Convert to AVIF/WebP button next to live savings stats (before/after size, percentage saved per format).

Front end (content rewriting)

• Optional <picture> rewrite in the_content and post thumbnails — browsers automatically pick the lightest format they support.
• Lookup of attachment IDs from URLs is cached in the WordPress object cache (Redis/Memcached when available) and memoised per request, so heavy pages with many images stay fast.

Tools & admin UI

• Cleanup tool — remove old generated .avif / .webp sidecars by age (30/60/90/120 days) and folder scope, with a per-folder picker.
• Admin bar download — optional link on singular posts/pages to download the original JPG/PNG of the featured image (useful for social platforms that don’t accept AVIF/WebP).
• Event log — last 100 events (errors, conversions, queue runs) visible on the settings page.
• Three-option uninstall dialog — when removing the plugin you choose between Cancel, Remove (keep generated files) or Remove and delete files.

Privacy & dependencies

• No external services, no remote calls, no tracking. Everything runs on your own server.
• Requires PHP 8.3+ and PHP GD with WebP support (imagewebp). AVIF is optional.
• Fully translated to Polish; English source strings ready for further translations via GlotPress.