Yes, descriptive alt text helps SEO by clarifying images, improving accessibility, and adding indexable context for search.
Alt text sits inside your image markup and tells both assistive tech and search engines what that picture represents. Write it for people first, and you also give crawlers clearer signals. That mix leads to better image visibility, stronger topical relevance on the page, and a smoother reading experience.
What Alt Text Actually Does
Alt text is a short description inside the alt="" attribute of an <img> tag. Screen readers announce it when the image can’t be seen. Bots parse it to better understand the subject. If an image is a link, that text can work like anchor text. When it’s concise and on-topic, it reinforces the surrounding copy and helps images surface in the right searches.
Think of it as a caption for machines that echoes the human intent of your page. Done well, it reduces ambiguity: a “brown leather messenger bag on a desk” beats “image123.jpg” every time.
Common Image Scenarios And What To Write
Use this early reference to pick the right approach and avoid guesswork.
| Scenario | Alt Approach | Sample Alt Text |
|---|---|---|
| Product photo on a shop page | Describe model, color, variant | “Men’s navy trail jacket, waterproof, front view” |
| Logo in the site header | Brand name; if link to home, name the site | “Acme Tools” |
| Decorative flourish/divider | Empty alt (alt="") |
“” |
| Chart or graph | Short alt + details in nearby text | “Quarterly revenue trend, 2022–2025” |
| Button that’s an image | Describe action | “Add to cart” |
| Headshot in author box | Person’s name | “Samira Khan” |
| Infographic | Short alt + full text on page | “Steps for cold-brew coffee” |
| Social icons | Name the destination | “Instagram” |
| Image that repeats nearby text | Empty alt | “” |
How Alt Text Helps Search Visibility
Search systems read nearby copy, filenames, and alt text to figure out what an image shows and whether it matches a query. Clear descriptions nudge images toward the right results and reinforce the page topic. On pages where images carry core meaning—recipes, products, tutorials—that little attribute can tip the scales for relevance and clicks from image surfaces.
There’s another perk: when an image doubles as a link, the description can act as the anchor. That gives crawlers a better hint about where the link leads and keeps the experience cleaner for screen reader users.
When To Leave The Alt Empty
Not every image needs words. If a picture is purely decorative or repeats text that’s already present, use an empty attribute: alt="". Screen readers will skip it, which keeps people from hearing needless clutter. Icons used only for style, background flourishes, and repeated brand marks often fall into this bucket.
How To Write Descriptive Alt Text
Match The Page Goal
Describe what the image contributes in this spot. A muffin photo on a bakery menu might need flavor and frosting. The same shot in a photography tutorial might call out lighting and lens choice.
Stay Specific, Not Spammy
Pick concrete words—object, action, and any detail that changes meaning. Skip stuffing a pile of keywords. One clear phrase beats a noisy string every time.
Keep It Short
One phrase or one sentence is plenty for most images. If you need more, place the full description in nearby text and keep the attribute brief.
Avoid Redundancy
Don’t start with “Image of” or repeat captions verbatim. If the surrounding line already spells out the same thing, the attribute can be empty.
Use People-first Language
If a person’s identity matters to the meaning, include it. If not, name the role or action (“baker frosting cupcakes,” “teacher at a whiteboard”).
Real-World Writing Examples
Blog Tutorial
Context: teaching readers how to knot a tie.
Weak: “tie steps.” Better: “Hands forming a Windsor knot, step 3.”
Ecommerce
Context: category page for trail shoes.
Weak: “shoe.” Better: “Women’s trail runner, sage green, side profile.”
Local Business
Context: café homepage hero.
Weak: “coffee shop.” Better: “Barista pouring latte art into a ceramic cup.”
Accessibility Rules That Also Help Search
Accessibility guidance maps cleanly to search outcomes. A short, accurate description helps people using assistive tech and gives crawlers the right label for the image. Two resources to keep handy:
- Google image SEO best practices — see the section on filenames, titles, and alt text.
- W3C alt text decision tree — a quick flow to decide when to write text and when to use empty alt.
Myths, Busted
“You Must Hit A 125-Character Limit”
There’s no fixed cap. Screen readers handle longer strings, but short and pointed reads better and keeps the flow.
“More Keywords = More Rankings”
Stuffing a list of synonyms in the attribute degrades the experience and can look spammy. One crisp description is all you need.
“Every Single Image Needs A Description”
Not true. Decorative images and repeated visuals can and should use empty alt to reduce noise.
Quick Style Rules For Clean Alt Writing
- Use sentence case; no ALL CAPS.
- Skip filler stems like “Photo of.”
- Call out text that appears only in the image.
- For charts and maps, add a short summary in the attribute and the full detail in nearby copy.
- For image buttons, name the action (“Search,” “Submit order”).
Quality Checks And Maintenance
Run A Screen Reader Pass
Toggle VoiceOver, NVDA, or Narrator and tab through a few key pages. Listen for clarity. Fix anything that sounds vague or repetitive.
Spot-Audit With DevTools
Inspect a handful of <img> tags. Confirm you have either a useful phrase or an empty attribute. Watch for images used as CSS backgrounds where information could be lost to bots and assistive tech.
Track Image Traffic
Use Search Console to check image surfaces for the pages that rely on visuals. Better alt writing tends to improve matching queries and click-through on the image view.
Editorial And Engineering Workflow
Give Writers The Context
In briefs, include why each image exists. “Show the frost pattern on the leaf” yields better text than “leaf.jpg.”
Standardize Filenames And Captions
Descriptive filenames and on-page captions support the same goal: clarity. Keep all three—filename, caption, and alt—aligned without copy-pasting the same sentence.
Handle Complex Visuals
When a graphic carries dense data, pair a short attribute with a paragraph that states the key takeaway. People using assistive tech get the same result as sighted readers.
Alt Text Length, Tone, And Examples
Use this mid-page cheat sheet to keep writing tight and relevant.
| Item | Recommended | Notes |
|---|---|---|
| Typical length | 1 short phrase or 1 sentence | Expand in nearby text for complex images |
| Tone | Plain, descriptive, specific | No ALL CAPS; no “Photo of” |
| Keyword use | Only if natural | Never stuff synonyms |
| Empty alt cases | Decorative or redundant visuals | Use alt="" |
| Linked images | Name the destination or action | Acts like anchor text |
| People | Name or role if relevant | Skip demographics unless they change meaning |
Filename, Captions, And Page Context
Search engines don’t look at the attribute alone. Filenames, captions, surrounding headings, and the page topic all feed the same decision. Give each image a short, human filename, keep captions tight, and make sure the copy near the image talks about the same thing. That harmony helps crawlers match your picture to the right query and helps readers scan the page.
Snag-Free Implementation Tips
HTML First
Embed real images with <img> rather than CSS backgrounds when the picture carries meaning. That makes it discoverable, indexable, and accessible.
Responsive Images
Use srcset or <picture> with a proper fallback and keep the attribute present on the fallback image. That way every client sees the description.
CDN And Sitemaps
If images live on a CDN, make sure the files are discoverable and referenced with consistent URLs. Image sitemaps help large libraries get crawled.
A Fast Checklist You Can Paste Into Briefs
- What does this image add to the page? Write that.
- One phrase or one sentence—no fluff.
- Use names, models, colors, or actions that matter.
- Skip if decorative or redundant (use empty alt).
- If it’s a link, name the action or target.
- For data visuals, add the key takeaway in body text.
- Keep filename and caption aligned with the same idea.
Bottom Line That Drives Wins
Clear alt writing improves access, sharpens relevance signals, and helps images earn clicks. Treat it like any other microcopy craft: brief, concrete, and tied to the page’s goal. Build it into your content process and you’ll see steadier image traffic and a better experience for every reader.