Alt Text for SEO: Image Alt Text Examples & Rules

Alt text is the alt attribute on an <img> tag: a short written description of what an image shows. For SEO, good image alt text describes the image in plain, specific words, uses the page’s keyword only when that is genuinely what the picture shows, and stays under about 125 characters. Google uses alt text together with computer vision and the surrounding page to understand images, which is what gets them into Google Images, and screen readers read it aloud to people who cannot see the image.

That is the whole job in one paragraph. Below: what Google actually does with alt text, alt text examples for the image types you publish most, how to handle decorative images, and what we found when we checked 2,241 images on pages that currently rank in the top 10 for on-page SEO queries.

What alt text is

The alt attribute lives on the image element:

<img src="/img/serp-preview.png" alt="Google result preview showing a title cut off at 600 pixels" />

It appears in three places. Screen readers read it in place of the image. Browsers show it when the image fails to load. And search engines read it as the text equivalent of the image, the same way they read the words on the rest of the page. It is sometimes called an “alt tag”, but it is an attribute of the <img> tag, not a tag of its own. The other image-related markup sits in the head and is covered in meta tags in HTML.

Does alt text help SEO?

Yes, in three specific ways, and not in the way it is often sold.

• Image search. Google’s image SEO guidelines say it uses alt text along with computer vision and the page’s content to understand the subject of an image. An image with accurate alt text on a relevant page is the one Google can confidently show for an image query.
• Images as links. When an image is wrapped in a link, its alt text works as the anchor text for that link. A logo linking home with alt="SEO Worth home" passes a description; one with no alt passes nothing.
• Page relevance, a little. Alt text is page text. It adds to the topical picture of the page in the same small way a caption does.

What it will not do is lift a page in web search on its own. The question “does image alt text actually make a difference for SEO?” is a long-running thread on r/SEO precisely because people add keyword alt text and see nothing move. The honest answer is that alt text is hygiene: missing it wastes the only text signal an image has, and stuffing it is a risk, but a perfect alt is not a ranking lever.

What 2,241 images on top-ranking pages tell us

To see how ranking pages handle alt text in practice, we fetched the top 10 organic results for 12 on-page SEO queries (US results from DataForSEO, 2026-10-05) and parsed every <img> element in each page’s HTML. 101 pages were readable; 91 of them had at least one image.

What we checked	Result	n
Images with descriptive alt text	1,277 (57.0%)	2,241
Images with an empty alt (alt="")	762 (34.0%)	2,241
Images with no alt attribute at all	202 (9.0%)	2,241
Pages where every image had an alt attribute	60 (66%)	91
Median images per page	16	91
Median length of a non-empty alt	22 characters	1,277
Middle half of non-empty alts	13 to 39 characters	1,277
Non-empty alts over 125 characters	28 (2.2%)	1,277

How to read it:

• Empty alt is common and correct. A third of the images were deliberately marked decorative: icons, dividers, avatars, background art. That is what the spec asks for.
• Missing alt is still everywhere, even on SEO pages. One page in three that ranks for an SEO query has at least one image with no alt attribute. If it is common on pages about SEO, it is common on yours.
• Good alt text is short. The typical descriptive alt was 22 characters, about four words. Very few ranking pages write paragraph-length alts.

What this does not show: we read raw HTML without running JavaScript, so lazy-loaded images inserted by scripts are not counted. We did not judge whether each alt was accurate, only whether it existed and how long it was, and the sample covers one topic area. It describes what ranking pages do, not what caused them to rank. Tracking pixels with a width of 0 or 1 were excluded.

How to write alt text for SEO

1. Describe what the image shows

Write what a sighted reader gets from the image, as if you were describing it over the phone. “Bar chart of click-through rate by position, dropping from 28% at position 1 to 2% at position 10” is useful. “Chart” is not.

2. Be specific, then stop

Name the thing, the key detail and the context, then stop. Aim for 5 to 15 words. You do not need “image of” or “picture of”: screen readers already announce that it is an image.

3. Use the keyword only when it is true

If the page is about title tags and the image is a screenshot of a title tag in a SERP preview, “title tag” belongs in the alt because it describes the picture. If the image is a stock photo of a laptop, the alt should say “laptop on a desk”, not “title tag SEO”. Matching the image honestly is what makes the alt useful to Google in the first place.

4. Put the information in charts and screenshots into words

For a chart, give the takeaway and the key numbers. For a screenshot of an interface, say what it shows and what matters in it. If the data is too long for an alt, keep the alt short and put the detail in a caption or the body text next to it.

5. Mark decorative images with an empty alt

Icons next to text labels, divider lines, background textures and decorative illustrations should have alt="". That tells screen readers to skip them. Leaving the attribute off entirely is not the same: many screen readers then read the file name, which is how readers end up hearing “IMG underscore 4021 dot JPEG”.

6. Describe the destination for linked images

When an image is a link and there is no other text in the link, the alt should describe where the link goes. A logo linking to the homepage gets alt="SEO Worth home", not a description of the logo’s colours.

7. Do not repeat the caption

If a visible caption already says exactly what the image shows, a short alt is enough. Screen-reader users hear both, so word-for-word duplication just makes them listen twice.

Image alt text examples

Image	Bad alt	Good alt
Product photo	shoes	Nike Pegasus 41 running shoe in blue, side view
Chart	chart	Line chart: impressions rose from 1,700 to 6,500 over two months
Software screenshot	screenshot	SERP preview showing a 640px title truncated after the word "Examples"
Team photo	team	Five members of the support team at the Lisbon office
Recipe step	cake recipe best cake easy cake chocolate cake	Chocolate cake batter being folded with a rubber spatula
Logo used as a home link	logo.png	SEO Worth home
Infographic	infographic about meta tags	Infographic: the 6 meta tags that affect SEO (detail in the body text)
Decorative divider or icon	decorative swirl	"" (empty alt)

The recipe row is the pattern Google itself warns about: alt text that is a list of keywords rather than a description. It is the most common form of keyword stuffing still around, because image alt fields are often filled in bulk by a plugin or by someone working through a checklist.

Alt text vs title attribute, caption and file name

Field	Who sees it	SEO weight	Fill it?
alt attribute	Screen readers, search engines, broken images	The main text signal for images	Always (empty if decorative)
Caption	Every visitor	Counts as page text	When the image needs context
File name	Search engines, people who download it	Small	Use words, not IMG_4021.jpg
title attribute	Mouse users on hover only	Little or none	Optional; never instead of alt

How to audit alt text on a page

1. Spot-check in the browser. In the DevTools console, document.querySelectorAll('img:not([alt])') lists images with no alt attribute, and document.querySelectorAll('img[alt=""]') lists the ones marked decorative. Check that the second list really is decorative.
2. Crawl the site. A crawler such as Screaming Frog reports images missing alt text and alt text over a length you set. Sort by alt to find duplicates; the same alt on 300 product images usually means a template filled it.
3. Read your important images aloud. For the five images that matter most on a page (product photos, charts, screenshots), read the alt without looking at the image. If it does not tell you what you would have seen, rewrite it.
4. Check the rest of the page with it. Alt text is one item on the on-page SEO basics checklist. The heading outline is another, and it matters to the same screen-reader users: see H1 tag SEO.

The bottom line

Give every image an alt attribute. Describe what informative images show in 5 to 15 specific words, use your keyword only when it honestly describes the picture, and leave decorative images with an empty alt. That serves screen-reader users, gives Google the text it needs for image search, and keeps image links meaningful. The ranking pages we checked do exactly this with short, plain alts, and a third of them still leave some images without one, which is an easy gap to close on your own pages.

For the text-side signals that sit next to your images, see SEO title examples and best practices and meta tags for SEO.

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[ FAQ ]

What is alt text in SEO?

Alt text is the `alt` attribute of an HTML `<img>` element: a short text description of the image. In SEO it helps Google understand what the image shows, which matters for Google Images and for the relevance of the page, and it acts as the anchor text when an image is a link. It is also what screen readers read aloud, which is its original purpose.

Does alt text help SEO?

Yes, mainly for image search and for images used as links. Google says it uses alt text together with computer vision and the page's content to understand images. Alt text on its own will not lift a page's ranking in web search, but missing or stuffed alt text wastes the one text signal an image carries.

How long should alt text be?

Long enough to describe the image, short enough to listen to: usually 5 to 15 words, or under about 125 characters. Google sets no limit. The 125-character figure comes from older screen reader behaviour and is best treated as a readability guide. The median alt text on the ranking pages we checked was 22 characters.

Should I put keywords in alt text?

Only when the keyword describes the image. Alt text for a screenshot of a title tag in a SERP preview can naturally include 'title tag'. Alt text that lists keywords unrelated to the image is keyword stuffing, which Google names in its image guidelines and spam policies.

Do decorative images need alt text?

They need an alt attribute, but it should be empty: `alt=""`. An empty alt tells screen readers to skip the image. A missing alt attribute makes many screen readers read the file name instead, which is worse than silence.

What is the difference between alt text and an image title attribute?

Alt text replaces the image for people and machines that cannot see it, and Google uses it to understand the image. The title attribute shows a tooltip on hover, is not read reliably by screen readers, and carries little or no SEO weight. If you only fill one, fill the alt.