Alt text (the alt attribute on an <img> element) serves two purposes: it tells search engine crawlers what an image depicts, and it provides a text alternative for users who cannot see the image.
From an SEO perspective, images without alt text are invisible to crawlers. Missing alt text on product images means those images cannot rank in Google Image Search and contribute no keyword signal to the surrounding page.
What SearchVitals checks: The On-page SEO audit scans all crawled pages and flags images with empty, missing, or suspiciously short alt attributes as a warning or critical finding depending on the proportion affected.
Good practice: Write alt text that describes what the image shows in plain language. Decorative images that add no informational value should use an empty alt attribute (alt="") so screen readers skip them.