FAQ

FAQ

Does it modify my original images?

No. Originals stay byte-for-byte identical. The plugin writes sibling files (photo.jpg.webp, photo.jpg.avif) and never opens a source for writing.

You can verify it. Take a checksum before and after a bulk run:

find wp-content/uploads -type f \( -name '*.jpg' -o -name '*.png' \) \
  -printf '%p %s %T@\n' | sort | sha256sum

Why are some formats shown as "claimed" rather than "verified"?

The library says it supports the format, but the plugin's encoding test failed. Those formats stay disabled on purpose — this is exactly the situation that produces corrupted images with no visible error.

AVIF is generated but never delivered. Why?

Your server is probably returning .avif files with the wrong MIME type. See Delivering images.

Can I run it alongside another optimizer?

Yes, though delivery stays off while one is active. See Migrating.

Do I need Imagick?

No. GD is enough, provided it was built with WebP and AVIF support — most modern PHP 8.1+ builds are. The Diagnostics screen tells you exactly what you have.

Why is thumbnail optimization greyed out?

No lossless tool is installed for that format. No PHP library can recompress a JPEG without degrading it; that genuinely requires jpegoptim or jpegtran. PNG works through GD when nothing better is available.

Does it work with WooCommerce?

Yes. Product images and galleries go through the standard WordPress filters the plugin hooks. Gallery zoom attributes are left untouched, so lightboxes keep working.

Does it work with a CDN?

<picture> mode does, and this is one of its main advantages: the HTML is identical for every visitor, so caching behaves normally. .htaccess mode requires Vary: Accept, which in practice disables CDN caching of images.

What about page caching?

<picture> mode is cache-safe for the same reason.

Will it slow down my site?

Conversion happens in the background, not during a page load. On the front end, the plugin adds a small number of cached database lookups per page.

Does it send anything anywhere?

No. There is no telemetry, no API, no account. The only outbound request is a HEAD to your own site, to check how it serves an .avif file.

Where are the converted files?

Next to the originals, with the format appended: 2024/01/photo.jpg → 2024/01/photo.jpg.webp.

The extension is appended rather than replaced so photo.jpg and photo.png in the same folder cannot collide.

What happens when I delete an image?

Its derivatives are deleted with it, including when WordPress regenerates thumbnails or you restore an edited original.

What happens if I uninstall?

Nothing is removed, unless you first enable Uninstall on the Advanced tab. Deactivating never removes anything.

Can I use it on multisite?

The plugin runs per site. It has not been tested extensively on multisite; treat that as unverified rather than supported.