Requirements & Compatibility
Understand compatibility checks, supported environments, and graceful fallback behavior.
Vacuum is built to degrade safely. Missing AVIF support does not block WebP, missing frontend delivery support does not modify stored URLs, and skipped files are reported rather than processed blindly.
Compatibility matrix
| Capability | Required for | Fallback |
|---|---|---|
| Imagick WebP write | WebP generation and WebP source optimization | GD WebP when available |
| GD WebP write | WebP generation | Imagick WebP when available |
| AVIF read/write | Optional AVIF generation | WebP and originals continue |
| Writable uploads | All file output | Optimization is blocked |
| Writable backups | Backup-first restore | Disable backups only with care |
| WP-Cron | Scheduled backup cleanup | Manual cleanup may be needed |
Browser compatibility
Frontend delivery keeps original fallback markup available. Visitors whose browsers support AVIF or WebP can receive the modern format; others receive the original image.
Multisite notes
The plugin follows WordPress upload paths and table prefixes. Test each site in a multisite network separately before enabling upload automation broadly.
WooCommerce and gallery plugins
Vacuum integrates through WordPress image functions and media metadata. It works best with themes and plugins that use WordPress attachment APIs rather than hard-coded image URLs.