Harvify Image Optimizer for WebP and AVIF

Harvify Image Optimizer helps WordPress administrators convert Media Library images to modern WebP and AVIF formats without running heavy compression work inside PHP.

The plugin scans lightweight attachment metadata first, then your browser converts selected images in a small queue. Images are processed with Web Workers and OffscreenCanvas where available, uploaded back through authenticated WordPress REST API requests, and released from browser memory as each item finishes.

This client-side approach is designed for shared hosting environments where PHP memory limits and execution timeouts can interrupt large image optimization jobs.

Key features

• Convert JPEG, PNG, WebP, and AVIF source images to WebP or AVIF.
• Scan one source format at a time so existing target-format images are not
  accidentally reprocessed.
• Select a few images for a test run before processing the full queue.
• Skip small files, very large images, selected upload paths, or filename
  patterns.
• Lazy-load images on the front end.
• Media Library “Optimize now” row action — convert and replace a single
  image straight from the Media Library list, using the same in-browser engine
  as the bulk queue.
• PNG to JPEG preset — one click in the optimizer switches PNG sources to a
  JPEG target, which is usually far smaller for photographs.
• Restore an image you replaced — put the original file back for a single
  attachment, in the free tier.
• Total optimized and KB saved — how many images you have optimised and how
  much space that has saved, totalled across the whole library.
• Adjust quality and queue concurrency from the admin screen.
• Save queue state in the browser with IndexedDB so work can resume after
  interruption.
• Keep wp-admin responsive by doing conversion work in browser workers.
• Process images locally in your browser without using an external optimization
  API.
• Optional original-file deletion, disabled by default.

Pro features (Harvify Pro Bundle)

• Automatic front-end delivery — your pages serve WebP/AVIF through a
  element with the original as the fallback, so browsers that cannot
  read the new formats still get an image. Covers post content and featured
  images.
• Keep originals, and restore — convert to sidecar variants instead of
  replacing the file, then restore a single image or bulk-restore every
  generated variant in one action.
• Auto-queue new uploads — images uploaded from now on are marked for the
  next run, so the library does not drift back out of date.
• Media Library status column — see at a glance which attachments are
  optimised, and which queue items are WooCommerce product images.
• Savings reports with CSV export — how much space you have actually
  reclaimed, per format, plus a debug log you can copy into a support request.
• Per-format quality control — separate WebP, AVIF and JPEG quality settings
  rather than one slider for everything.

Privacy and external services

Harvify Image Optimizer does not send images to a third-party compression service, load scripts from external CDNs, or track usage. Images are fetched by your browser from your own WordPress site and uploaded back to your own WordPress REST API.

AVIF encoding uses bundled WebAssembly encoder files. The current AVIF path uses the Apache-2.0 licensed @jsquash/avif single-thread encoder, with the earlier bundled wasm-avif encoder retained as a local fallback.

Format testing

If you want to experiment with AVIF conversion outside your WordPress Media Library first, you can use this browser-based test tool:

AVIF to PNG Converter

External services

This plugin connects to Freemius, the licensing and update service Harvify uses to
sell and deliver the Pro tier of its plugins.

Nothing is sent to Freemius unless you choose to send it. The plugin ships in
anonymous mode, so a fresh install makes no outbound request at all, and the free
tier stays fully usable if you never opt in. Data is transmitted only when you take
one of these actions:

• You click “Allow & Continue” on the Freemius opt-in screen. This sends your
  site address, your administrator email address, and your WordPress, PHP and active
  plugin/theme details, so Harvify can provide support and know which environments to
  test against. Skipping that screen sends nothing and leaves the plugin working
  normally.
• You enter a Pro Bundle licence key. This sends the key together with your site
  address so the licence can be activated for that site. While a licence is active the
  site also re-checks periodically that it is still valid and whether a Pro update is
  available.

Service provided by Freemius, Inc. – https://freemius.com/
Terms of service: https://freemius.com/terms/
Privacy policy: https://freemius.com/privacy/

Image conversion

Conversion runs entirely inside your own browser using WebAssembly encoders bundled
with the plugin. Images are read from, and written back to, your own WordPress site.
No image is sent to any third-party service and no external CDN is used.