What Is Alt Text?

A screen reader can announce this text to someone who does not perceive the image visually. A browser may expose it when the file fails to load. Search systems can use it as one contextual input when interpreting the relationship between an image and its page.

Alt text is not a visible caption, filename, hover tooltip or hidden keyword field. It belongs to the specific use of the image on that page. The same photo may require different alternatives when it functions as a product example, a linked button or a decorative background.

1. Identify the exact page, asset, entity or relationship described in this section.
2. Inspect the live implementation and retain the observed evidence.
3. Compare the observation with the intended meaning and its primary specification.
4. Correct any mismatch, then retest the live result.
5. Record the accountable owner and review date.

• Describe meaning or function, not every pixel.
• Use an empty alt for purely decorative images.
• Let nearby copy carry complex detail.

Primary specification: W3C Web Accessibility Initiative image guidance.

Alt text preserves an image’s meaningful contribution in words, based on what the image does in its current context.

When an image carries information, omitting its alternative can remove that information from a nonvisual experience. A linked image without useful alt text may leave the destination unclear. An unlabeled product color, chart result or instructional screenshot can block a task even when the rest of the page is accessible.

For SEO, accurate alternatives help connect an asset with the page topic, but relevance comes from the complete page: visual content, heading, caption, filename, surrounding copy and technical delivery. Stuffing terms into alt attributes harms clarity and cannot replace a useful image or page.

• The exact page, asset, entity or relationship covered by this section
• The live implementation rather than an editor-only preview
• The primary specification or first-party record defining the expected behavior
• The validation result, accountable owner and review date

1. Identify what the image contributes.
2. Decide whether it is meaningful, functional or decorative.
3. Write the smallest complete alternative.
4. Test it within the surrounding page.

Alt text matters most as an accessibility requirement and earns SEO value by describing real visual meaning accurately.

Start with the page purpose. Include details that change the reader’s understanding or decision, such as a product model, visible color, chart trend or interface state. Omit details that add no value. Punctuation can help screen-reader phrasing, while sentences are appropriate when the visual conveys a complete finding.

Avoid opening with “image of” unless the medium itself matters, and avoid repeating a caption verbatim. Do not insert words merely because they are search targets. If a description becomes long, move the detailed explanation into visible text and keep the alt attribute focused.

1. Identify the exact page, asset, entity or relationship described in this section.
2. Inspect the live implementation and retain the observed evidence.
3. Compare the observation with the intended meaning and its primary specification.
4. Correct any mismatch, then retest the live result.
5. Record the accountable owner and review date.

• Read the paragraph without the image.
• Add only the missing essential meaning.
• Review language in the rendered page context.

Good alt text is context-specific, concise, accurate and sufficient to preserve the image’s purpose.

For a product page, “Black waterproof hiking boot, left side” distinguishes the visible variant. For an article chart, “Organic signups increased from 420 in January to 690 in June” communicates the result. For a screenshot, “Crawl report filtered to pages returning 404” names the interface state that supports the instruction.

The same words are not reusable everywhere. A team photograph on an About page may identify named people, while the same crop used as a decorative banner should have an empty alt attribute. A logo linking home needs a destination or brand alternative; an adjacent visible brand name may make repetition unnecessary depending on the link content.

• The exact page, asset, entity or relationship covered by this section
• The live implementation rather than an editor-only preview
• The primary specification or first-party record defining the expected behavior
• The validation result, accountable owner and review date

1. Name the relevant subject.
2. Add the distinguishing state or detail.
3. State the conclusion for data visuals.
4. Remove wording already supplied nearby.

An example is good only when it substitutes for the actual role of that image on that particular page.

An empty attribute tells assistive technology that the image can be skipped. Omitting the attribute is different: some tools may announce the filename or treat the image as unlabeled. Decorative dividers, background flourishes and repeated icons beside visible text are common empty-alt candidates.

Do not label an image decorative merely because writing its alternative is difficult. A chart, product photo, warning icon, instructional screenshot or linked image usually conveys meaning or function. If a complex visual already has a complete nearby explanation, the alt text can be brief and point conceptually to that explanation rather than restating every value.

1. Identify the exact page, asset, entity or relationship described in this section.
2. Inspect the live implementation and retain the observed evidence.
3. Compare the observation with the intended meaning and its primary specification.
4. Correct any mismatch, then retest the live result.
5. Record the accountable owner and review date.

• Always include the alt attribute on img elements.
• Distinguish empty from missing.
• Judge redundancy in the complete accessible context.

Use empty alt only when removing the image from a nonvisual reading would remove no information and no action.

Product alternatives should identify the item and only the visible variation that matters: color, angle, material or included component. Gallery images can distinguish front, back, detail and in-use views. Avoid copying a long product title into every image because repeated announcements reduce usefulness.

Charts require more than “bar chart.” State the trend or comparison and place detailed values in a nearby table when they matter. Screenshots should identify the application area, selected control or observed result. Sensitive account details should be removed from the image itself, not merely omitted from its alt text.

• The exact page, asset, entity or relationship covered by this section
• The live implementation rather than an editor-only preview
• The primary specification or first-party record defining the expected behavior
• The validation result, accountable owner and review date

1. Identify the user’s task.
2. Select only task-relevant visual facts.
3. Write a concise alternative.
4. Add visible long-form detail where required.

Match the alternative to the visual task: choosing a product, understanding data or completing an interface step.

A specific, accurate alternative helps connect the visual with the page’s subject. It can also make the page more usable, which is valuable independently of search traffic. The strongest opportunities occur when an image is genuinely useful for a visual query, such as a product, diagram, location, example or process.

Do not rewrite alternatives to chase every keyword variation. Review the broader Image SEO workflow: crawlable image URLs, stable responses, responsive sizing, modern formats, dimensions and relevant surrounding copy. Image delivery can also influence Largest Contentful Paint and Cumulative Layout Shift.

1. Identify the exact page, asset, entity or relationship described in this section.
2. Inspect the live implementation and retain the observed evidence.
3. Compare the observation with the intended meaning and its primary specification.
4. Correct any mismatch, then retest the live result.
5. Record the accountable owner and review date.

• Optimize the whole image-page relationship.
• Keep alternatives truthful and user-centered.
• Measure traffic without sacrificing accessibility.

Alt text supports image SEO most effectively when it describes a useful visual naturally inside a technically sound page.

Start with product, landing, article, category and application templates that receive traffic or support revenue. Extract image URL, alt value, link context, caption, nearby text and component type. Automated checks can identify missing attributes, suspicious repetition and empty alternatives, but they cannot decide whether the words preserve meaning.

Perform a human review with images hidden or a screen reader. Confirm image-only links have useful accessible names and decorative assets stay silent. Test localization: translated pages need alternatives in the page language, not copied source-language text. Record defects by shared component so one correction can improve many pages.

• The exact page, asset, entity or relationship covered by this section
• The live implementation rather than an editor-only preview
• The primary specification or first-party record defining the expected behavior
• The validation result, accountable owner and review date

1. Inventory important image components.
2. Classify each image role.
3. Run automated issue detection.
4. Review meaning with images unavailable.
5. Fix shared components and retest.

An alt-text audit is complete only when high-value images have contextually correct alternatives and decorative images are intentionally silent.