One converted image proves the point — a full library pays the bandwidth bill. PixSpeed gives you three routes to get there, from a single dashboard button to a WP-CLI run you can schedule at 3 AM. All three convert every generated size of every image, skip what is already done, and leave your originals untouched.
Option 1 — The dashboard bulk converter (recommended)
- Open PixSpeed → Dashboard.
- Find the Bulk converter card and press Start Bulk Conversion.
- Watch the progress bar — PixSpeed processes a configurable number of images per batch (default 3) so the server stays responsive.
- The live log lists every file: converted, skipped or failed, with the reason.
- When it finishes, the stats cards update with files converted and space saved.
The run is resumable by design: if anything interrupts it, just press the button again — finished images are skipped automatically.
Option 2 — The media library bulk action
For targeted batches — say, one month of uploads:
- Go to Media → Library in list view.
- Select the checkboxes of the images you want.
- Choose Convert to WebP/AVIF from the bulk actions dropdown and hit Apply.
Option 3 — WP-CLI for large libraries
Thousands of images? Run it from the terminal — no browser timeouts, no PHP limits:
# See engines and current stats
wp wac status
# Convert everything, in chunks, skipping finished images
wp wac convert all --limit=50 --skip-existing
# Convert specific attachments only
wp wac convert 123 124 125
# Undo everything (deletes variants, keeps originals)
wp wac restore all --yes
wp wac convert all --limit=100 --skip-existing
After the run — purge your page cache
With the default Picture tag serving mode your HTML does not change, so purging is optional — the next render already wraps images correctly. But if you use the legacy URL swap mode, or simply want cached HTML refreshed everywhere immediately, purge your page cache after the bulk run.
FlynCache Purge serving modes explainedWhat happens to new uploads?
SettingsFrequently asked questions
How long does a bulk conversion take?
Roughly 1–3 seconds per image size on a typical host, depending on engine and image dimensions. A 500-image library with several sizes each usually finishes within minutes. The dashboard shows live progress, so you always know where you are.
Can visitors browse the site while it converts?
Yes. PixSpeed processes in small batches precisely so your server stays responsive. On very weak shared hosting, lower the batch size in Settings or run the conversion via WP-CLI at night.
The run stopped halfway — what now?
Nothing to fix. The log shows exactly which images finished. Start the bulk converter again: already-converted images are skipped and the run continues from where it left off.
Will my disk usage grow?
Slightly — variants are extra files next to your originals. What shrinks is what visitors download: served images drop 25–50% in size. The PixSpeed dashboard shows the full picture in its stats cards.
