How Alt Text Affects SEO

What alt text actually does

Alt text (the alt attribute on an <img> tag) has two separate jobs, and both matter for a site’s search performance:

1. Accessibility. Screen readers read the alt text aloud in place of the image — a blind or low-vision visitor’s only way to know what an unlabeled image contains. This isn’t optional under WCAG 1.1.1 (the baseline accessibility standard most legal requirements point to), and it’s the reason accessibility-lawsuit risk keeps coming up in the same conversation as SEO: the ADA and the EU’s Accessibility Act (in force since June 2025) both treat missing alt text as a real compliance gap, not a nice-to-have.
2. Search ranking. Google Images can’t “see” a picture the way a human does — it reads the alt text (plus surrounding page context) to understand what’s in it and when to surface it for a relevant search. No alt text, or generic alt text like image1.jpg or just "image", means Google has nothing to rank the image on. For a lot of sites (recipe blogs, e-commerce, photography, real estate), Google Images traffic is a meaningful, often-overlooked acquisition channel — and it compounds for free once the alt text is right, unlike paid traffic.

What “good” alt text looks like

• Describes what’s actually in the image, specifically — not “photo” or the filename.
• Short: a sentence, not a paragraph. Screen readers read it in full every time.
• Skips “image of” / “picture of” — screen readers already announce it’s an image; it’s redundant.
• Includes relevant keywords only when they’re actually true of the image — keyword-stuffing alt text as an SEO trick reads badly to screen reader users and Google both penalize and can detect it.

Why this is tedious to do by hand

A site with a few hundred images means a few hundred alt-text fields to write, one at a time, in the WordPress media editor. Most sites just don’t — which is the gap AltPilot closes: alt text and a caption generated automatically on upload, or in bulk for an existing library, following the guidance above by default (the model is instructed to describe what’s actually there, skip “image of”, keep it concise).

Check where you stand

Run the free alt-text scanner on your own domain — it crawls your images, flags which are missing or weak, and generates a few sample alt texts so you can see the difference before installing anything.