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Low proportion of images using modern formats

Most of the images on your site are still using older file formats (JPEG or PNG) rather than modern formats like WebP or AVIF, which deliver the same visual quality at a significantly smaller file size.

Why this matters

Larger image files slow page load times and can push up your Largest Contentful Paint (LCP) score, a Core Web Vitals metric Google reports. Modern formats such as WebP and AVIF are often considerably smaller than JPEG or PNG at similar visual quality, though savings vary by image.

How to fix it

Ask your developer to convert images to WebP or AVIF format and serve them instead of JPEG/PNG. Many image tools, CDNs and website platforms can automate this conversion, so check whether yours does (if you use WordPress or Shopify, for example, look for a built-in setting or an image optimisation plugin or app). Keep fallbacks for older browsers.

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