Description

AVIF Local Support adds modern AVIF image support to WordPress while keeping compatibility with existing JPEG media. Built by a Boston photographer who needs it for their own portfolio website.

GitHub Repository: https://github.com/ddegner/avif-local-support

Local-first: all processing happens on your own server — no external calls. Works well for me on a shared CPU with 2GB of RAM on Linode.
Image quality first: uses Imagick PHP and CLI when available for high-quality resizing (LANCZOS), corrects EXIF orientation, and preserves ICC color profiles and EXIF/XMP/IPTC metadata when possible.
Tunable quality and speed: set AVIF quality (0–100) and encoder speed (0–10) to balance fidelity and performance. You can even adjust choose chroma subsampling (4:2:0, 4:2:2, 4:4:4) and bit depth (8/10/12-bit). Defaults: 4:2:0 and 8-bit if your server supports it and you want higher quality images.
Wraps existing <img> tags in <picture> with an AVIF <source> when an .avif version is present.
Converts JPEG originals and generated sizes to AVIF on upload, or via a daily/background scan.
Preserves EXIF/XMP/IPTC metadata and ICC color profiles by default (when using ImageMagick/Imagick).
WordPress-aware resizing logic enabled by default to avoid double-resizing when generating AVIF sizes from originals.
- Tools include: convert missing AVIFs, upload a test JPEG, and delete all AVIF files in uploads.

How it works

Front end: Filters common image outputs to add an AVIF <source> ahead of the original JPEG. Browsers that support AVIF will use it; others fall back to JPEG.
Conversion: Uses Imagick when available (preferred) — with auto-orientation and LANCZOS resizing — or GD with an AVIF encoder. Quality, speed, chroma subsampling, and bit depth are configurable (subsampling/bit depth applied via Imagick when supported).
Scheduling: Optional daily scan to backfill missing .avif files for existing JPEGs.

Requirements

PHP 8.0 or later (8.1+ recommended)
WordPress 6.5 or later
Imagick PHP extension recommended for best quality and metadata/ICC preservation. GD fallback supported.

Ubuntu/Debian setup (summary)

For local JPEGAVIF conversion you need either Imagick with AVIF-enabled ImageMagick, or GD with AVIF support:

Imagick path (recommended)
- PHP extension: imagick
- System libraries: ImageMagick built with HEIF/AVIF support (via libheif)
- Notes: This path enables higher-quality resizing and preserves metadata/ICC profiles
GD path (fallback)
- PHP extension: gd built with AVIF support (provides imageavif on PHP 8.1+)
- Notes: Ensure your distro’s PHP GD is compiled with AVIF; some builds omit it
Helpful extras
- PHP exif extension (for orientation handling in the GD fallback)
- Web server configured to serve .avif as image/avif (Apache/Nginx/LiteSpeed)

Official documentation:
– PHP Imagick installation: https://www.php.net/imagick
– PHP GD installation (AVIF details): https://www.php.net/manual/en/image.installation.php
– ImageMagick format support (AVIF/HEIF): https://imagemagick.org/script/formats.php
– Apache MIME configuration: https://httpd.apache.org/docs/current/mod/mod_mime.html
– Nginx MIME configuration: https://nginx.org/en/docs/http/ngx_http_types_module.html

Screenshots

Settings — configure AVIF conversion and output.
Tools — convert missing AVIFs, test a conversion, and delete AVIFs.
Status — server capability check and library coverage.
About — in-admin readme for quick reference.

Installation

Upload the plugin files to the /wp-content/plugins/avif-local-support directory, or install via the WordPress Plugins screen.
Activate the plugin through the ‘Plugins’ screen in WordPress.
Go to Settings AVIF Local Support to configure options.

FAQ

Does this modify my original JPEGs?: No. It creates .avif files alongside your existing JPEG originals and sizes.
Will this slow down uploads?: If “Convert on upload” is enabled, some servers may take longer to process uploads due to AVIF generation. You can disable this and use the scheduled/background conversion instead.
Do I need Imagick?: Imagick is recommended for the best results and for preserving metadata and color profiles. If Imagick is not available, the plugin falls back to GD where supported.
Does it track users or send data externally?: No. The plugin does not track users or send data to external services.
ImageMagick CLI not detected on LiteSpeed/CyberPanel due to open_basedir?: On LiteSpeed/CyberPanel, the vhost sets a restrictive open_basedir (e.g., /tmp:/home/<site>). PHP’s is_executable('/usr/local/bin/magick') returns false under that restriction even when the binary exists and works from the shell. The plugin currently relies on is_executable and bails out instead of offering a fallback or a guided fix.
Why do I see a “High risk of memory exhaustion” error in the logs?: The plugin now estimates memory usage before processing to prevent fatal errors (crashes) on servers with limited RAM. If you see this, try switching to the “ImageMagick CLI” engine or increasing your PHP memory_limit. As a last resort, you can check “Disable memory check” in the settings to bypass this safety measure.

Reviews

There are no reviews for this plugin.

Contributors & Developers

“AVIF Local Support” is open source software. The following people have contributed to this plugin.

David Degner

“AVIF Local Support” has been translated into 1 locale. Thank you to the translators for their contributions.

Translate “AVIF Local Support” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.

Changelog

0.2.3

Support: Automatically rewrite parent anchor links to point to AVIFs (improves compatibility with lightboxes like SimpleLightbox).

0.2.2

Reliability: Added pre-conversion memory check to prevent fatal errors on low-RAM servers.
Settings: Added “Disable memory check” option for advanced users who want to bypass safety limits.
Logs: Improved error reporting with actionable suggestions (highlighted) for memory limits, missing delegates, and configuration issues.
Logs: Include memory check status in conversion log details.

0.2.1

Admin: Add Logs panel to Tools with refresh/clear and detailed entries (status, engine, duration, sizes, settings, errors).
Admin: Add “Run ImageMagick test” diagnostic action with inline CLI output and exit code.
Tools: Show inline progress with a progress bar and faster polling during Convert now.
Scheduling: Respect site timezone and selected time; reschedule daily task if time changes.
Engine/CLI: Improve binary validation, set env paths for Homebrew modules, retry transient delegate/read errors, and add helpful AVIF support hint when no output.
Uploads: Allow .avif uploads via WordPress mime filter.
Output: Remove stray XML declaration from HTML output when using picture tag replacement.
Docs: Add FAQ for LiteSpeed/CyberPanel open_basedir causing is_executable to return false.

0.2.0

Engine: Add ImageMagick CLI support as alternative to Imagick extension with auto-detection of available binaries.
Engine: New engine selection settings with automatic detection of ImageMagick CLI installations.
Admin: Improved header styling to match WordPress metabox design patterns.
Admin: Enhanced tab navigation with better CSS handling and removal of Status tab.
Admin: Added reset defaults functionality for settings management.
UI: Better spacing and visual consistency in admin interface.

0.1.8

Performance: Optimize Imagick conversion by using single instance for both processing and metadata extraction, reducing memory usage and file I/O operations.

0.1.7

Bugfix: Correct AdobeRGB desaturation by preserving ICC from a fresh read and only adding nclx when untagged; continue to prefer Imagick so ICC survives.

0.1.6

Color: Preserve ICC profiles when present; add sRGB nclx only when no ICC.
Color: Avoid transforming tagged images; transform untagged to sRGB to prevent desaturation.
Color: Explicitly set AVIF nclx to sRGB/full range when applicable.
Orientation: Normalize EXIF Orientation to 1 after auto-orienting to prevent double-rotate.
UI: Status tab warns when GD is the preferred method about lack of color management.

0.1.5

Tools: Add “Delete all AVIF files” action with security checks.
Admin: Show “Running…” on convert start and poll progress more frequently.
Admin: Increase spacing and add non-breaking spaces between radio options.
Admin: Place “Convert now” under file input in Upload Test.
Status: Deduplicate counts by real JPEG path to avoid double-counting.

0.1.4

Defaults: Always preserve metadata (EXIF/XMP/IPTC) and ICC color profiles.
Defaults: Always avoid double-resizing by using WordPress original/-scaled logic.
Settings: Remove toggles for metadata/ICC/avoid double-resizing (now defaults).
Settings: Add chroma subsampling radios (4:2:0, 4:2:2, 4:4:4) and bit depth radios (8/10/12-bit). Defaults: 4:2:0 and 8-bit.
Security: Continue strict sanitization of new settings with whitelists.
Docs: Update descriptions to reflect new defaults and controls.

0.1.3

Cleanup: remove unused admin-post “Convert now” handler; AJAX is the single path.
Cleanup: simplify deactivation routine to directly clear scheduled hooks.
Cleanup: remove unused global polling object and helpers in assets/admin.js.
Internal: no user-facing changes; reduces complexity and maintenance overhead.

0.1.2

Security: ensure all settings use sanitize_callback and validate/escape inputs consistently
Admin: sanitize GET/FILES handling for the Tools Upload Test
Prefix: standardize on aviflosu_* options/defines and Ddegner\\AvifLocalSupport namespace
Docs: update contributor username to ddegner

0.1.1

Improve accessibility and settings labels; better time input handling for scheduled conversions
More robust DOM handling for wrapping images and avoiding double-wrapping
UI: clearer Convert Now button text and styling on the settings page
Minor performance and reliability improvements in scheduling and conversion pipeline

0.1.0

Initial release.