What it is
The module creates WebP copies (and AVIF, when the server allows it) of each image and serves the lightest version the visitor's browser accepts. The original image stays exactly as you uploaded it.
How to use it
- The Essential profile already prepares lighter versions without changing the page HTML.
- The Recommended profile starts serving them on the page.
- Images already on your site are converted little by little, in the background, without slowing it down.
- To replace a photo without hunting page by page, use "Replace file" in the Media Library: the new file takes the old one's place, with the same name, on every page. "Undo replacement" brings the previous one back.
- The "Clean up the library" tab shows how much space you can free: photos that appear nowhere, the same photo uploaded several times, sizes from an old theme and huge originals. Everything goes to the trash or to a 30-day safe folder, with Undo.
- Optional: "Good file names for Google" gives new photos with a phone name (IMG_2034) the name of the page they were uploaded from.
Common problems
The AVIF option doesn't show up.
AVIF depends on PHP features on the server (recent Imagick or GD). Without them the plugin uses WebP only.
An image looks odd.
Use "Restore all originals" in the Images screen: visitors see the original again right away.
A photo I use shows up as "unused".
It happens with a photo used only by the code of the theme or of another plugin, not saved in a page. Don't send it to the trash; if you did, restore it in the "Clean up the library" tab itself.
I replaced the photo and still see the old one.
The plugin changes the photo's address on the page so the browser fetches the new one. If the site uses another CDN or cache besides Ranking's, clear that cache.
If something goes wrong
Turn off the Images module. Lighter copies are only deleted on uninstall if you tick that option.
Didn't find the answer? Ask in the WordPress.org support forum.