Alt text is a short written description added to an image in HTML so screen readers and search engines can understand what the image shows. For SEO, it helps search engines interpret image content, supports accessibility, and gives you another quality signal to review when checking on-page optimization. If a page relies on product photos, charts, or screenshots, missing or vague alt text can weaken both usability and image search visibility.
What alt text does on a page
Alt text sits inside the image tag and is meant to describe the image itself, not stuff in extra keywords. Search engines use surrounding page content, file names, and image context together, but alt text still helps confirm relevance. For site owners running an SEO check, this matters most on pages where images carry meaning: product pages, service explainers, blog tutorials, comparison tables turned into graphics, and location pages with branded visuals.
If the image is purely decorative, the correct choice is often an empty alt attribute rather than a forced description. That tells assistive technology the image can be skipped. A common quality issue is seeing the same repeated alt text across dozens of images, which adds little value and can look careless.
How to review alt text during an SEO audit
When auditing a page, check whether important images have alt text that is specific, accurate, and aligned with the page topic. Good alt text describes what is visible and, when relevant, the function of the image. It should not repeat the page title word for word unless that is genuinely what the image shows.
- Describe the image clearly in a few words.
- Keep it specific to the page context.
- Avoid keyword stuffing and generic labels like "image" or "photo".
- Use empty alt text for decorative images.
- Check templates so product galleries and blog images are not left blank sitewide.
Practical example of strong vs weak alt text
Imagine a page about technical SEO audits showing a screenshot of a crawl report with blocked pages. Weak alt text would be: "SEO audit" or "image123". Stronger alt text would be: "Crawl report showing blocked pages and noindex URLs". The stronger version helps users who cannot see the image and gives search engines clearer context about the visual.
What alt text can and cannot improve
Alt text can improve accessibility, image relevance, and overall page quality signals, but it will not rescue a weak page on its own. If a page has thin copy, indexing problems, poor internal linking, or slow performance, rewriting image descriptions will not fix the larger issue. Treat alt text as one checkpoint inside a broader SEO review: confirm the page can be crawled, indexed, understood, and used easily, then tighten image descriptions where they add real meaning.