FAQ
Does the add-on change my original images?
Section titled “Does the add-on change my original images?”No, unless you switch on Compress original images. Then every original is backed up before it is re-saved, Restore originals puts it back, and uninstalling the add-on restores it too. WebP and AVIF copies are separate files in images/kv_image_optimizer_webp/.
CS-Cart can already save thumbnails as WebP. Why this add-on?
Section titled “CS-Cart can already save thumbnails as WebP. Why this add-on?”The core setting Settings → Thumbnails → Format: WebP converts thumbnails only, sends WebP to every browser without a fallback and has no AVIF, no compression of originals, no lazy loading and no report. This add-on also covers the full-size product images (zoom and lightbox), banners and other images, adds AVIF, keeps the original as the fallback and shows what it saved. Both can be used together: thumbnails the core already writes as WebP get an AVIF copy only.
Will customers with old browsers see broken images?
Section titled “Will customers with old browsers see broken images?”No. With the default Picture element delivery the original image stays in the page; browsers that do not know AVIF or WebP simply load it.
Does it work with the full page cache (Performance Booster) in CS-Cart 4.21?
Section titled “Does it work with the full page cache (Performance Booster) in CS-Cart 4.21?”Yes. Every visitor gets the same markup and the browser picks the format, so a cached page is correct for everyone. Storefront requests never write to the database.
Does it work with a CDN?
Section titled “Does it work with a CDN?”Yes, with the CloudFront CDN of CS-Cart: the copies are served by the CDN like any other image. Images stored on Amazon S3 instead of the server are not supported.
My host disables exec() and shell functions. Is that a problem?
Section titled “My host disables exec() and shell functions. Is that a problem?”No. The add-on uses only PHP’s GD or Imagick extension, never external programs.
The page says AVIF is not supported.
Section titled “The page says AVIF is not supported.”AVIF needs PHP 8.1 or newer with AVIF in GD, or Imagick with AVIF. Without it the add-on creates WebP copies, which already save most of the bytes. When your host adds AVIF support, click Create all copies again.
How much disk space do the copies need?
Section titled “How much disk space do the copies need?”Roughly half to two thirds of your images folder for WebP and AVIF together. Copies that would not be smaller are not kept. Turn AVIF or image groups off, or exclude files, to save space.
Will optimising slow down my store?
Section titled “Will optimising slow down my store?”No. Images are converted by cron, by the Optimise now batches or in short background batches while you use the admin panel, never while customers browse. The storefront only checks whether a copy exists.
I replaced a product image. Will the old WebP show?
Section titled “I replaced a product image. Will the old WebP show?”No. A copy is only served while it is newer than its image, and the add-on deletes the copies of replaced images at once. The new image shows as the original until its copies are made by the next run.
Some images are skipped.
Section titled “Some images are skipped.”The files list shows the reason: animated images (kept as they are so they keep moving), images over the megapixel limit, images with a colour profile other than sRGB or in CMYK when only GD is available (Imagick converts them), unreadable files, or a copy that would not be smaller.
What happens if the license lapses?
Section titled “What happens if the license lapses?”Without a valid license (no key after the 14-day start period, an invalid or revoked key, a domain the license does not cover, or no successful check for 14 days), no new images are converted or compressed and the storefront shows the original images without the picture element or lazy-loading changes. Nothing is deleted and no image breaks: compressed originals stay valid, the copies stay on disk, and Restore originals and Delete optimised copies keep working. Once the license is valid again, everything is back.
The admin panel shows a license notice.
Section titled “The admin panel shows a license notice.”Open Add-ons → Manage add-ons → Image Optimizer (WebP/AVIF & Lazy Load) → Settings → License. The status line says what is wrong: no key, a key for another add-on, a revoked license, or a domain that the license does not cover. Fix it and click Check now. See License.
Does the add-on work on my staging copy?
Section titled “Does the add-on work on my staging copy?”Yes. Subdomains of your licensed domain (for example staging.example.com) and local development hosts (localhost, private IP addresses, *.local, *.test) are covered by the same license.
What happens if your license server is down?
Section titled “What happens if your license server is down?”Nothing changes for 14 days: the add-on keeps working and retries every hour. Only if no check succeeds for 14 days is it switched off until the next successful check.
Does the license check slow down my storefront?
Section titled “Does the license check slow down my storefront?”No. The check runs only in the admin panel or from cron, at most once a day, never while customers browse.
Still stuck?
Section titled “Still stuck?”Work through the troubleshooting guide, then contact support with your CS-Cart version, edition, PHP version and the add-on version (1.0.0).