Alt text (alternative text) is a short written description added to an image's HTML so that screen readers and search engines can understand what the image shows.
Alt text lives in an image's HTML as the alt attribute and describes the image's content and function for people using screen readers, for browsers when an image fails to load, and for search engines that can't literally "see" an image the way a human can. Good alt text is concise and specific — describing what the image actually shows and why it's there, rather than stuffing it with keywords. Decorative images that add nothing meaningful to the content are usually given empty alt text (alt="") so screen readers skip over them, rather than describing something irrelevant. Meaningful images — product photos, diagrams, infographics — should have alt text that genuinely conveys what someone would miss by not seeing the image.
Alt text is primarily an accessibility feature, making a site usable for people relying on screen readers — but it also gives search engines genuine information about image content, which can help images surface in image search and gives search engines a little more context about the page overall.
Illumae's site audit flags images without alt text as part of every crawl, so you can find and fix the gaps across your whole site rather than checking page by page.
Meaningful images do. Purely decorative images (background textures, spacers) are usually better served with empty alt text so screen readers skip them rather than reading out something irrelevant.
No. Alt text should accurately describe the image. Keyword-stuffed alt text reads badly for screen reader users and search engines are generally good at identifying when it’s unnatural.
It’s not a major direct ranking factor for the page as a whole, but it does help images appear in image search results and contributes to overall accessibility, which search engines do care about.
No credit card required. See real output for your own business before you pay anything.