Delivering strong imagery with a usable loading experience

Image performance starts before final compression. Decide what the photograph communicates, which detail must survive a crop and whether motion adds useful information. Keep high-quality originals and clear usage rights.

Define the first-screen image

Choose a clear subject such as material, environment or a meaningful brand scene. Check desktop and mobile crops. Keep headings, specifications and actions as real page content rather than embedding everything in the image.

Agree on responsive delivery

Define display sizes, density, formats and fallbacks with the implementation team. HTML srcset and sizes support resource selection; picture can support different crops or formats. Review the output visually rather than optimizing file size alone.

• Preserve essential product detail and colour.
• Treat important first-screen assets differently from lower-page images.
• Reserve image dimensions to limit layout movement.
• Provide appropriate text alternatives for informative images.

Measure in context

The good Core Web Vitals thresholds described by web.dev are LCP at most 2.5 seconds, INP at most 200 milliseconds and CLS at most 0.1, assessed at the 75th percentile of real visits. A single lab score does not establish field performance or a ranking guarantee.

Keep editorial rules usable

Provide image ratios, export guidance and a review checklist. Recheck crops, clarity and loading after major media changes. Record the page, device, network and method when comparing measurements.

Reference: web.dev: Web Vitals.

Reference: MDN: responsive images.