Alt Text Best Practices for SEO: What Website Owners Need to Know

Introduction

Alt text describes what an image shows or communicates. It also helps people using screen readers understand images on a webpage. In September 2026, Google added a new way to track visual search activity in Search Console, giving site owners more insight into how people find their content through images.

Understanding alt text best practices for SEO in 2026 can help website owners review their image descriptions and make better use of this new performance data.

The update does not introduce a new alt text ranking rule. The practical priority remains the same: describe images accurately, use the right alternative for each image’s purpose and check that the content works for people as well as search engines.

What Is Alt Text and How Does Google Use It?

Alt text is an HTML attribute that provides a text alternative for an image. Screen readers use it to communicate relevant image information to people who cannot see the image. Google also uses alt text alongside page content and computer vision to understand what an image shows.

The description should fit the image and the page where it appears. A photograph on a product page may need to identify a particular product feature. The same photograph used in a tutorial may need to explain something different.

Alt text is not the same as a caption or image title. A caption usually appears beside the image on the page, while alt text is supplied through the HTML alt attribute.

For example, an image of a red bicycle with a front basket could use:

alt=”Red city bicycle with a front basket”

This identifies the subject and a distinguishing detail. It does not need a list of related search terms.

Google explains how alt text contributes to image understanding in its Image SEO best practices documentation.

What Has Changed in Image Search in 2026?

In September 2026, Google added multimodal search reporting to Search Console. Website owners can use the new filter to examine performance from searches involving Google Lens, Circle to Search, image uploads and Chrome’s “Search this image” feature.

Google's Multimodal Search Reporting

The report gives website owners another way to investigate how people discover their pages through images. It may be useful for sites with product photography, diagrams or other visual content.

What Website Owners Can Learn

Check whether visual search brings visitors to important pages and look for changes in performance over time. If a page attracts relevant image-based traffic, review whether its images are described accurately and whether the surrounding content explains them clearly.

Search Console does not assess individual alt text attributes, so use the report to identify areas for investigation rather than as a measure of alt text quality.

Google announced this reporting update on 24 September 2026. It changes the performance data available in Search Console, not the established guidance for writing alt text.

Alt Text Best Practices for SEO

The aim is to give each image a useful description, not to fit a keyword into every available attribute. These are the checks worth making when writing or reviewing image alt text.

Use Keywords Naturally in Alt Text

A keyword can fit into alt text, but only when it describes the image. There is no benefit in squeezing the main search term into every image description.

For example, a bicycle maintenance guide might include a close-up of a rear derailleur.

Poor example:

alt=”bike cheap bike buy bike online best bike bicycle bike deals”

Better example:

alt=”Rear derailleur on a blue commuter bicycle”

The second example identifies what is actually shown. If the image appears in a guide to adjusting a derailleur, the surrounding text can explain the repair process. The alt text does not need to carry the entire SEO message.

Google also advises against stuffing alt text with keywords. Describe the image clearly, and include a search term only when it fits naturally.

Describe the Image in Its Page Context

An image can serve different purposes on different pages, so its alt text should reflect what the reader needs to know.

For example, a laptop image on a product page might show its design. In a tutorial, the same image could help readers find a setting or follow a step.

Avoid labels such as alt=”photo” or alt=”image1″. They offer little useful information. Stick to what the image shows and leave out details you cannot verify.

Keep Alt Text Concise

Alt text does not have a fixed character limit under WCAG. The aim is to explain the relevant parts of an image without adding words that serve no purpose.

A product photo may need only a few words. A chart is different. Its alt text might give a short overview, while a longer explanation elsewhere on the page covers the data in detail.

There is no need to hit a set word count. Keep the description brief where possible, but include the details someone would miss if they could not see the image.

Use Descriptive Image File Names

Before uploading an image, give it a name that tells you what it shows. A file named blue-commuter-bicycle.jpg is easier to understand than IMG_1048.jpg.

Google uses file names to help understand images, but they are only one of several signals. Keep names short and clear. There is no need to add several keywords to the same file name.

Remember that file names and alt text do different jobs. A useful file name helps identify the image, while alt text describes it for people who cannot see it. One does not replace the other.

Place Images Near Relevant Text

Google considers the content of the page when interpreting images. Place each image near the text that explains or relates to it, and make sure the page itself covers the same subject.

A photograph of a bicycle brake belongs naturally beside the instructions for adjusting that brake, rather than in an unrelated section. This gives readers a clearer experience and provides search engines with more context.

For larger websites, an image sitemap can also help Google discover images that might otherwise be difficult to find. It supports image discovery; it does not replace good descriptions or guarantee indexing.

For more detail, read our guide to Google’s recommendations for optimising images for search.

Quick Checks for Better Alt Text

Before publishing or updating an image, check four things:

Context: Does the description explain the image’s purpose on that page?
Accuracy: If AI helped write it, have you checked the details against the actual image?
Length: Is the wording concise without leaving out important information?
Search performance: Where relevant data is available, use Google Search Console to investigate visual search traffic. Remember that the report does not assess alt text quality.

These checks build on Google’s existing image SEO guidance and accessibility principles. They are practical recommendations, not new Google requirements.

How Should Alt Text Differ by Image Type?

The right description depends on what an image contributes to a page. An informative photograph, a decorative divider and an icon that activates a button should not all be treated in the same way.

Informative and Product Images

Describe the information that distinguishes the image. For a product photograph, this might include its colour, material or a feature that helps users tell it apart from other products.

For example:

Less useful: alt=”Product image”

More useful: alt=”White ceramic mug with a blue handle”

The second description gives the reader a clearer idea of what is shown. Avoid adding sales claims such as “best mug for every home”. Alt text should describe the image, not turn it into an advert.

Decorative Images

Some images exist only to improve a page’s appearance. Examples include decorative borders, visual flourishes and illustrations that repeat information already provided in nearby text.

These images should generally use an empty alt attribute:

alt=””

This allows screen readers to skip the image rather than announce details that add nothing to the page. The attribute should not simply be omitted, as some screen readers may announce the image’s file name instead.

Whether an image is decorative depends on its purpose in context. An illustration may be decorative on one page but informative on another.

Functional Images and Buttons

When an image acts as a button or link, its alternative should explain what the control does or where it leads.

For example, a magnifying-glass icon used as a search button needs an accessible name such as “Search”. Describing it only as “magnifying glass” identifies its appearance but not its function.

If a linked image repeats the same information as adjacent link text, an empty alt attribute may be appropriate to avoid repetition. The complete link or control must still have an accessible name.

Charts, Graphs and Infographics

A short description may not convey everything contained in a complex chart or diagram. In these cases, use alt text to identify the graphic and summarise its purpose, then provide a fuller explanation or equivalent data in accessible text.

For example:

alt=”Bar chart comparing monthly website visits across three regions”

If the exact figures and trends matter, make them available in a table or accompanying explanation. Do not expect one short sentence to communicate every detail of a complex visual.

What Are the WCAG 2.2 Alt Text Requirements?

WCAG 2.2 Success Criterion 1.1.1, Non-text Content, addresses text alternatives for non-text content, subject to specified exceptions. The alternative should serve an equivalent purpose, whether that means explaining information in an image or identifying the function of a control.

WCAG 2.2 and Text Alternatives

The key requirement is not simply to fill in an alt attribute. The alternative must be appropriate to the image.

An informative image needs a description of its relevant content. A functional image needs an alternative that communicates its action or destination. A decorative image should generally have an empty alt attribute so that it does not create unnecessary screen reader output.

For complex images, a short alternative may need to point to a fuller description elsewhere on the page. The additional text should be available to users who need it, not hidden from them.

What UK Website Owners Need to Know

UK public-sector websites and mobile apps are subject to the Public Sector Bodies Accessibility Regulations, within the scope and exceptions of those rules. Current government guidance identifies WCAG 2.2 Level AA as the standard for meeting the requirements.

These regulations should not be presented as applying in the same way to every private-sector website. Other accessibility duties may apply depending on the organisation and service.

Website owners should check the requirements relevant to their circumstances and include image alternatives in wider accessibility reviews. Writing suitable alt text is important, but it does not by itself make an entire website compliant.

Can AI-Generated Alt Text Be Trusted?

AI tools can draft descriptions for large image libraries, but their output needs checking before publication. A description can sound convincing while missing the point of the image or including details that are not actually visible.

Consider a photograph of a worker wearing protective equipment. An automated tool might identify the helmet and high-visibility jacket correctly but miss that the photograph illustrates a particular safety procedure. The final description should reflect the information the page is intended to communicate.

A useful review process is straightforward:

Check the generated description against the actual image.
Remove details that are inaccurate or irrelevant.
Confirm whether the image is informative, decorative or functional.
Make sure the wording fits the image’s purpose on the page.

AI can help with the first draft, especially when a site contains many images. It should not decide the final alternative without appropriate review. The aim is not to make every description longer or more detailed; it is to make each one accurate and useful.

How to Audit Existing Alt Text

A useful alt text audit starts with the images that matter most to visitors. Check key landing pages, product pages and articles before working through the rest of the site.

Find Missing and Empty Alt Attributes

Use a crawler such as Screaming Frog SEO Spider to export image URLs, alt attribute values and the pages where images appear. Filter the results for missing alt attributes and empty values.

An empty value is not automatically an error. Decorative images should generally use alt=””, so check the image’s purpose before flagging it.

Check Whether Descriptions Match the Images

Open the pages containing flagged images and compare each description with the actual image. Look for vague text such as “image1”, repeated descriptions on different products, and wording that includes details the image does not show.

Check functional images separately. A search button needs an accessible name that explains its action, not simply a description of its icon.

Automated tools can identify potential problems, but they cannot reliably decide whether every description conveys the right meaning in context.

Test Accessibility and Review Search Data

Open the page and check how a screen reader handles its images and buttons. Charts need a closer look too. If the figures matter, make sure readers can find them in text.

Next, check Google Search Console for visual search activity. Use the crawl results to spot possible alt text problems, then inspect the images yourself.

Keep a simple record of each issue: the page URL, image URL, existing alt text and change needed. Mark each item off once you’ve checked the fix.

Conclusion

Google’s 2026 multimodal Search Console reporting gives website owners another way to investigate visual search performance. It does not replace established alt text best practices for SEO or introduce a new ranking rule. Review descriptions for accuracy, use appropriate alternatives for different image types and check accessibility alongside search data. These steps provide a sound basis for maintaining useful image content as visual search develops.

Frequently Asked Questions

Did Google update its alt text guidelines in 2026?

Google announced new Search Console reporting for web multimodal search on 24 September 2026. This provides performance data for searches that use images; it does not announce a new alt text formula or ranking factor.

What is new in Google Search Console’s multimodal reporting?

The new filter lets website owners investigate performance from searches using Google Lens, Circle to Search on Android, image uploads to Google Search and Chrome’s “Search this image” feature. Metrics appear when a site receives relevant traffic.

Is there a fixed character limit for alt text?

There is no universal WCAG character limit for alt text. Keep the description concise while conveying the image’s purpose. Complex graphics may need a fuller explanation elsewhere on the page.

Should decorative images have empty alt text?

Yes. Images that serve only a decorative purpose should generally use alt=”” so assistive technology can ignore them. The attribute should be present, even when its value is empty.

Can AI-generated alt text be published without review?

Review is recommended. AI tools can misidentify objects, overlook context or include unsupported details. Check each description against the image and its role on the page before publishing.