PixSpeed's defaults are tuned so most sites never need to open Settings. But when you do — quality tuning, engine overrides, switching serving mode — this guide explains every switch and what it actually affects.
Where the settings live
PixSpeed → SettingsFormats — what gets converted
- Convert to WebP — master switch for WebP variants. On by default.
- Convert to AVIF — master switch for AVIF variants. On by default; PixSpeed simply skips AVIF automatically if no AVIF engine is detected.
.jpg.webp
.jpg.avif
Quality sliders
WebP quality AVIF quality| Goal | WebP | AVIF |
|---|---|---|
| Maximum savings (screenshots, thumbnails-heavy sites) | 70 | 50 |
| Balanced (default) | 82 | 60 |
| Portfolio / photography sites | 90 | 70 |
Engines — who does the conversion
auto- WebP: GD → Imagick → cwebp binary
- AVIF: Imagick → avifenc binary → GD
Two dropdowns let you override this per format — useful when one engine produces better results on your specific images, or when a host has multiple options. The PixSpeed dashboard shows the full detection table, so you always know which engine actually runs.
Serving
- Serve next-gen images — master toggle for delivery. Off means: convert only, keep serving originals.
- Serving mode — Picture tag (default), Server rewrite, or URL swap. Full walkthrough in the serving modes guide.
- Prefer AVIF over WebP — when a browser accepts both, offer AVIF first (it is smaller). Leave this on unless you have a specific compatibility reason.
Bulk processing
Batch sizewp wac convert all --limit=N
bulk conversion guide
Auto-convert on upload
Enabled by default. Every new image is converted the moment WordPress generates its sizes, so your bulk run stays a one-time backlog job. Disable it only if you want to review every conversion manually.
Integrations & maintenance
- FlynCache Purge — when active, a one-click purge button appears on the dashboard for after bulk runs (plugin guide).
- Recalculate stats — rebuilds the savings numbers after manual file changes.
- Restore all — removes every variant and keeps originals. Use before re-converting with new quality settings. variant files stay on disk if you later delete the plugin, unless you define
WAC_DELETE_FILESas true inwp-config.phpbeforehand.
Frequently asked questions
Do quality changes re-convert existing images?
No. New settings apply to images converted from that point on. To apply new quality to existing images, restore them and run the bulk conversion again — with --skip-existing removed, everything gets fresh variants.
What quality values should I use?
The defaults (WebP 82, AVIF 60) are a sweet spot modelled on common optimizer presets: visually indistinguishable from the original in most photos, with big savings. Raise to WebP 90 / AVIF 70 for portfolio-grade crispness; lower to WebP 70 / AVIF 50 if bandwidth is your top priority.
Can I convert WebP only and skip AVIF?
Yes — untick AVIF in Settings. WebP alone already cuts most of the weight and works on every modern browser; you can enable AVIF later without touching anything else.
