Image WebP Converter

Built by Aaron Belchamber — Business Growth & Cloud Systems Architect A standalone, zero-config WordPress plugin — no dependency on any other project. More: Brandager.com · Belchamber.us · Tools.Belchamber.us

Description

Automatically converts newly uploaded JPG/JPEG/PNG images to WEBP format on the fly, via the WordPress upload pipeline (wp_handle_upload) — not a directory batch-scan. This reduces image file size while preserving quality, improving page load times.

Features

• Converts JPG, JPEG, and PNG uploads to WEBP automatically as they come in.
• Preserves transparency for PNG images — and never drops below quality 80 for transparent images specifically, to avoid jagged compression artifacts on hard alpha edges.
• Corrects EXIF orientation before converting, so photos don't end up sideways.
• Skips CMYK JPEGs and hosts that can't decode WebP back, rather than risk a broken or corrupted result.
• Convert Existing Images: safely bulk-convert your current Media Library. Images not yet used anywhere convert immediately; images already in a post's content are converted with their references updated automatically, originals kept for your review; anything referenced from a page builder or widget is left untouched and reported, not guessed at.
• Cleanup Review screen to move reviewed originals to a holding folder (not deleted) once you're confident.
• Adjustable quality and an on/off toggle from the WordPress admin (Settings > WebP Converter).

Installation

1. Upload the image-webp-converter folder to /wp-content/plugins/.
2. Activate the plugin through the 'Plugins' menu in WordPress.

Usage

Once activated, every new JPG/JPEG/PNG upload is converted to WEBP automatically — nothing else to do. To convert images already in your Media Library, go to Settings > WebP Converter > Convert Existing Images.

Configuration

Quality (0–100) and the automatic-conversion toggle are set at Settings > WebP Converter in wp-admin. No file editing required.

Requirements

• PHP 7.4+
• GD extension enabled in your PHP configuration.

Support

Open an issue on this plugin's repository, or contact the developer via belchamber.us.

License

GPLv2 or later — see readme.txt for the WordPress.org-format changelog and FAQ.

Testing against hostile PHP environments

This plugin has four branches no single workstation can reach: a GD build that encodes WebP but cannot decode it, CMYK JPEG handling when Imagick is absent, a lossless path needing PHP 8.1's IMG_WEBP_LOSSLESS, and a PHP 7.4 imagedestroy() call. They are exercised by wp-dev-playground's PHP matrix:

scripts\test\run-php-matrix.cmd

Needs pip install -e E:\ab-code-projects\projects\wp-dev-playground and a container runtime (wpp doctor). All seven variants pass as of 2026-08-27.