On-Page & Content
Alternative Text (Alt Text)
The descriptive text attached to an HTML image tag, telling search engines and screen readers what an image shows.
What Is Alternative Text (Alt Text)?
Alt text (short for "alternative text") is a short description added to an image's HTML `alt` attribute. Search engines can't literally see an image the way a human does, so alt text is one of the primary ways a crawler understands what an image depicts and how it relates to the surrounding content. Alt text also serves a second, arguably more important purpose: accessibility. Screen readers used by visually impaired users read the alt text aloud in place of the image, so a missing or vague description (or a decorative image with no `alt=""` at all) creates a genuinely worse experience for real people, not just a missed SEO opportunity. Finally, alt text displays as a fallback label if an image fails to load — a slow connection, a broken file path, or a blocked resource will show the alt text where the image should be, which keeps a page usable even when images don't render.
Why Alternative Text (Alt Text) Matters for SEO
Accessibility comes first
Screen reader users depend on alt text to understand what an image conveys. This is a genuine usability requirement, not an SEO trick, and it should be treated as the primary reason to write good alt text.
Image search visibility
Well-described images can appear in Google Images results and occasionally drive meaningful referral traffic, particularly for visual-heavy niches like recipes, products, or design work.
Contextual relevance signal
Alt text contributes a small amount of topical context to the page it sits on, helping search engines confirm what the surrounding content is actually about.
A Simple Example
A blog post about home coffee brewing includes a photo of a pour-over setup. Weak alt text: `alt="image1"` or `alt="coffee"`. Strong alt text: `alt="Pour-over coffee dripper with a paper filter and kettle, mid-pour"` — specific, descriptive, and genuinely useful to someone who can't see the image, while also giving search engines real context about the scene.
Best Practices
- Describe what the image actually shows, as if explaining it to someone on the phone.
- Keep it concise — a sentence or short phrase is usually enough; avoid rambling paragraphs.
- Skip "image of" or "picture of" — screen readers already announce that it's an image.
- Use `alt=""` (empty, not missing) for purely decorative images so screen readers skip them entirely.
- Work the natural page topic into the description when it genuinely fits, without forcing it.
Common Mistakes to Avoid
- Leaving the `alt` attribute off entirely, which is worse for accessibility than an imperfect description.
- Keyword-stuffing alt text with repeated phrases that don't describe the image at all.
- Writing generic, copy-pasted alt text like "photo" or "graphic" across every image on a page.
- Using alt text as a place to cram marketing copy that has nothing to do with the visual.
Key Takeaways
- Alt text describes an image for search engines, screen readers, and failed image loads.
- Accessibility is the primary purpose; SEO and image-search traffic are secondary benefits.
- Good alt text is specific and concise, not keyword-stuffed or generic.
- Decorative images should use an empty `alt=""`, not a missing attribute.