Image optimisation is the fastest way to speed up a website, because in most cases images make up the largest share of the data transferred. The process has several steps. Upload images at the dimensions at which they are actually displayed, not at their original camera size, scaled down only in the browser. Use modern formats with better compression while preserving quality. Set up lazy loading for images below the first screen, but never for the main image at the top of the page. Specify dimensions so that content does not jump around while loading. And add descriptive text, which serves both accessibility and search. For online stores with thousands of products, it pays to set up automated processing instead of manual editing. Likewise, pay attention to the main image at the top of the page, which has the greatest effect on perceived speed and should load with priority.
See also: Core Web Vitals, Video on a landing page, Product feed.
