What it is
Alt text (short for "alternative text") is a short written description attached to an image in a page's code, using the alt attribute — for example, <img src="logo.png" alt="Blue mountain logo for [Business Name]">. It doesn't normally appear anywhere visible on the page itself; it exists as a description attached behind the scenes to that specific image.
From an SEO angle specifically, alt text is one of the only ways search engines have to understand the actual subject of an image, since they can't interpret a photo the way a person looking at it can — they largely depend on this text, the surrounding page content, and the filename to figure out what an image shows.
Why it matters
Images with clear, relevant alt text can be discovered and ranked in image-specific search results (like Google Images), which is an entirely separate traffic opportunity from your regular text-based search rankings — a well-optimized product photo, diagram, or infographic can bring in visitors who never would have found the page through a normal text search. Alt text also contributes, in a smaller way, to how search engines understand the overall topic of the surrounding page.
Missing alt text on meaningful images doesn't just skip that opportunity — pages with lots of unlabeled images can read, from a search engine's perspective, as thinner and less informative than they actually are to a human visitor looking at the same page.
How to fix it
- Identify images that convey real information — product photos, diagrams, infographics — as opposed to purely decorative images like background textures.
- Write a specific, concise alt description for each meaningful image, describing what it actually shows rather than repeating the page's title or stuffing in unrelated keywords.
- Leave purely decorative images with an empty
alt=""rather than a forced, irrelevant description. - If you're using a website builder or CMS, add alt text through the image's own settings panel (usually labeled "Alt text" or "Image description") rather than editing code directly.
- Re-run your Launch Readiness check to confirm your meaningful images now have alt text.