Direct answer
Images become more useful when they are relevant, efficiently delivered, dimensioned, surrounded by clear context, and given an alternative that serves the same purpose when needed.
Practical steps
- Decide whether the image is informative or decorative.
- Write functional alt text, not a keyword list.
- Use responsive formats and dimensions.
- Connect captions and structured data only to visible facts.
Common mistakes
- Stuffing alt attributes.
- Using images for essential text.
- Lazy-loading the likely LCP image.
Limitations
- Image search selection is not guaranteed.
- Automated alt generation needs human context.
Primary sources
- Creating helpful, reliable, people-first content — Google Search Central; 2025-12-10; 2026-08-14.
- Web Content Accessibility Guidelines (WCAG) 2.2 — W3C; 2024-12-12; 2026-08-14.