Image SEO and LCP: alt text, compression, and layout stability

Images drive clicks from image search, social cards, and Discover-style surfaces when they are relevant and fast. This guide balances accessibility (alt text humans need), performance (bytes and layout), and honest metadata search engines can trust.

9 min read Search visibility & SEO

Before you start

Ability to upload or regenerate media derivatives (hosting with image optimization helps but is not mandatory).

Write alt text for humans first

Describe what the image communicates in the article context — not a comma-separated keyword list.

Decorative dividers can use empty alt in HTML; WordPress “decorative” toggles vary by block — prefer correct semantics over SEO stuffing.

Serve the right pixel dimensions

Let WordPress generate srcset; avoid uploading 6000px originals if the theme never displays beyond 1200px.

For hero images, match the largest rendered width plus a modest retina margin.

Choose efficient formats without breaking old browsers

WebP or AVIF with JPEG/PNG fallbacks (plugin or CDN) typically cuts bytes dramatically.

After conversion, spot-check sharpness on text inside screenshots.

File names and surrounding text still matter

Use readable filenames before upload (annual-report-2026-chart.png) — not IMG_9831.jpg.

Place important images near the paragraph they illustrate; nearby text reinforces relevance.

Optional: image XML entries

Some SEO plugins extend sitemaps with image URLs — useful for large visual catalogs.

Keep image URLs HTTPS and non-redirecting; broken image URLs waste crawl budget.