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SparkCore

Faster WooCommerce shops with lighter product photos

Catalog and gallery images count double on mobile. Spark optimizes them in bulk.

Shop benefits

  • Smaller gallery loads
  • Better mobile experience
  • Less hosting bandwidth

Why product photos are the biggest snowball in an online store

A product page quickly displays a main image, a gallery, multiple variation thumbnails, and a row of related products. Multiply that by hundreds or thousands of products, and the total image load of an online store grows faster than on a regular content site. Slow product images also directly impact conversions: visitors don't like to wait for a category page that loads slowly.

Step-by-step plan: optimize your product catalog

Inventory your largest categories

Start with the categories that have the most products and variants. That's usually where the biggest gains are, because each variant often has its own set of images.

Choose a compression profile that suits product photography

Product photos with lots of detail, such as fabric, texture, or small parts, tolerate less aggressive compression than, for example, a logo or banner. Test the profile first on a few representative photos.

Process gallery and variation images in bulk

Don't just process the main image, but also gallery photos and variation thumbnails. These are often forgotten, yet together they determine a large part of the page size.

Visually check a sample of product pages

After processing, open a number of product pages, including the zoom function if you use one, and verify that details are still sharp enough.

Measure load time before and after

Compare a product and category page before and after optimization using a tool like Lighthouse or PageSpeed Insights, so you have the results in black and white.

Comparing formats for product photos

Not every format is automatically the best choice for product photos either:
FormatTypical savings compared to originalSuitable for
AVIFUsually the biggest savings; in our tests up to 94% smaller than the original.Main images and zoom photos with lots of detail, on browsers that support it.
WebPGenerous savings with broad support; usually 25 to 50 percent smaller than a comparable JPEG.Gallery and variation thumbnails as a broad fallback.
JPEG (optimized)Smaller gains than AVIF or WebP, but displayed everywhere.Product feeds and channels that only accept JPEG.
PNGLimited savings; only worthwhile when compressing properly.Product images with transparency, such as cut-out product photos.

Common mistakes with shop images

  • Compressing zoom images too aggressively, causing details to be lost when zooming in.
  • Only optimizing the main image and skipping variation thumbnails.
  • Not adding or checking alt text after optimization, even though it's important for product discoverability.
  • Leaving duplicate product galleries in place because both the theme and a plugin load images.
  • Not clearing the cache after a bulk run, so visitors still see the old, larger files.

Frequently asked questions

Yes. Variation thumbnails are processed along with everything else, so you don't need to handle them separately.

It depends on the compression profile you choose. Test the profile on a few representative product photos before processing your entire catalog, especially for photos with lots of fine detail.

Spark optimizes the underlying file, regardless of which gallery component your theme uses. It's best to test major theme or plugin changes on staging first.

Yes, as long as the images end up in your media library, they can be included in the processing.

The files in your media library change, so after making major changes, check that your feed is still delivering the correct, up-to-date images.

No. Optimization works on the underlying media file, which is usually shared across all language and currency variants.