Two goals, one set of actions

Image SEO serves two things at once: getting found in Google Images, and helping the page itself rank (mostly via speed). The good news is that the same handful of actions cover both — and most of them also make your images accessible. You optimize once, correctly.

The alt text: the single most important factor

Search engines can't see an image — they rely on the alt text to understand it. A clear, descriptive alt text ("red women's running shoe, side view") helps the image rank and lets screen readers describe it. Write it honestly for a human; that automatically serves the search engine too. Avoid keyword stuffing — modern search engines detect and discount it, and screen-reader users hear meaningless noise.

The file name

A descriptive file name is a small but real signal: red-garden-bench.jpg tells Google more than IMG_4821.jpg. Use lowercase, hyphens instead of spaces, and no special characters. It's a two-minute habit that helps both discovery and organization.

Context around the image

Search engines read the surrounding text to understand what an image is about — the caption, the heading nearby, the paragraph it sits in. An image about "sourdough bread" in an article about baking is understood better than the same image floating alone. Place images near relevant text, and use captions where they help.

Speed: the ranking factor everyone forgets

Images are usually the heaviest part of a page, and page speed is a ranking factor. So image optimization is image SEO:

  • Right format: photo → JPG/WebP, graphic → PNG/WebP/SVG.
  • Right size: don't serve a 4000-pixel image at 800 px; resize first.
  • Compress: quality ~80 (compression).
  • Responsive + lazy load below the fold, and a fast, prioritized hero image.

The full performance picture is in Improve Core Web Vitals.

Structured data and sitemaps

For the extra mile: image structured data (e.g. product images with schema) can enhance how images appear in search, and including images in your sitemap helps discovery. These are refinements — the foundation is descriptive alt text, good file names, relevant context and fast loading.

The mindset

The best image-SEO advice is also the simplest: optimize for people. Clear descriptions, real text instead of text baked into images, good context and fast loading serve users, screen readers and search engines alike. Accessibility and SEO aren't opponents — accessibility is the honest path to good SEO.