Prioritize Alt-Text for Accessibility and SEO

Improve accessibility, boost image SEO, and reach more users with clear alt-text—practical rules, templates, automation tips, and an implementation checklist.

Alt-text is the bridge between images and people or systems that can’t see them. Done well, it improves accessibility, supports SEO, and clarifies context for assistive tech and search engines.

• Write concise, contextual descriptions prioritizing meaning for users with visual impairments.
• Standardize with templates and governance to scale quality across sites and teams.
• Combine automated generation with human review to balance efficiency and accuracy.
• Optimize for SEO by including relevant terms naturally—never at the expense of accessibility.
• Measure quality with audits, user testing, and search metrics to iterate effectively.

Prioritize alt-text for accessibility and SEO

Images carry essential content: charts, diagrams, product visuals, and decorative elements. Alt-text ensures that non-visual users, screen readers, and search engines understand that content. Prioritizing alt-text means making it a standard part of content creation and publishing workflows.

Start by classifying images: functional (buttons, links), informative (charts, diagrams), decorative (patterns), and complex (infographics, maps). Prioritization should focus first on informative and functional images, then complex ones for detailed descriptions.

Quick answer

Write concise, descriptive alt-text that communicates the image’s purpose and content for non-visual users; include relevant keywords only when they are naturally part of that description, and pair automation with human review to scale while preserving accessibility.

Apply core principles for effective alt-text

Keep these principles front and center when writing alt-text:

• Purpose-first: Describe what the image conveys or how it functions on the page.
• Be concise: Aim for 5–15 words for simple images; longer for complex visuals where meaning requires it.
• Avoid redundancy: Don’t repeat nearby visible text unless the image adds new information.
• Context matters: Tailor descriptions to the page’s intent (e.g., product page vs. blog post).
• Decorative images: Use empty alt attributes (alt="") so screen readers skip them.

Examples:

• Product photo: “Blue waterproof hiking boot, mid-cut, men’s size 10.”
• Chart: “Bar chart showing 2024 Q1 revenue up 12% vs. Q4.”
• Decorative flourish: alt="" (no description).
• Button with icon: “Search” (button purpose, not visual details).

Standardize alt-text with templates and governance

Consistency drives quality at scale. Adopt templates and a governance model so writers, designers, and developers apply the same rules.

• Create short templates for common image types:
  • Product: “[color] [product name], [key attribute], [size/spec if relevant]”.
  • Chart: “[chart type] showing [metric] over [period], [key takeaway]”.
  • Avatar/profile: “[Name], [role] at [company]” (if publicly relevant).
• Define a policy document covering:
  • Which images require alt-text and which use alt="".
  • Preferred length ranges and forbidden practices (keyword stuffing, vague phrases like “image of”).
  • Approval and review roles: content owners, accessibility lead, QA.
• Embed alt-text requirements into CMS fields and templates so authors must enter text before publishing.

Automate alt-text generation with human review

Automation (computer vision, image-captioning models) accelerates coverage, but models make contextual and factual errors. Use automation to draft alt-text and route items for human review based on risk.

• Automation strategies:
  • On ingest: Auto-generate an initial alt-text candidate and flag it in the CMS.
  • Batch processing: Run models on legacy image libraries and queue items for review.
  • Confidence thresholds: Only auto-publish when model confidence and category indicate low-risk (e.g., decorative patterns).
• Human review best practices:
  • Prioritize review for product pages, legal/medical images, and images with people.
  • Provide editors with the template and a one-click approve/edit workflow in the CMS.
  • Track changes and model error types to fine-tune automation and training data.

Optimize alt-text for SEO without harming accessibility

SEO and accessibility often align: clear descriptions improve user experience and help search engines. But SEO should never override the primary goal—communicating meaning to non-visual users.

• Include keywords only when they are relevant and naturally part of the description.
• Avoid keyword stuffing and repetitive phrases like “image of” or “photo of.”
• Keep alt-text focused on the page’s intent—on product pages, include model names or SKU if useful to both users and search engines.
• Use structured data (schema) for product images, recipes, videos to provide machine-readable context in addition to alt-text.

Example that balances both:

• Good: “Red artisan ceramic mug, 12oz, speckled glaze” — includes product keywords naturally.
• Poor: “Image of a red mug ceramic pottery buy cheap mug red mug sale” — keyword stuffing, low accessibility.

Common pitfalls and how to avoid them

• Pitfall: Keyword stuffing. Remedy: Stick to context-first descriptions; allow SEO team to suggest keywords only when relevant.
• Pitfall: Leaving alt blank for informative images. Remedy: Enforce required alt fields in CMS and audit pages regularly.
• Pitfall: Overly short or vague alt-text (“graphic”, “logo”). Remedy: Use templates to require concrete attributes (brand, purpose, visible text).
• Pitfall: Auto-generated alt-text with factual errors (misidentifying people, objects). Remedy: Route high-risk images for human review and maintain a correction log.
• Pitfall: Describing purely visual style irrelevant to function. Remedy: Focus on function and meaning—describe style only if it conveys necessary information.

Measure alt-text quality and SEO impact

Set KPIs that cover both accessibility and search outcomes. Combine qualitative checks with quantitative metrics.

• Accessibility KPIs:
  • Percentage of images with non-empty alt-text where required.
  • Results from accessibility audits and automated linters (e.g., axe, pa11y).
  • User feedback or usability testing with screen reader users.
• SEO KPIs:
  • Organic image search impressions and clicks (Google Search Console).
  • Page-level organic traffic changes after alt-text updates.
  • Indexed images count and structured data validation.

Implementation checklist

• Classify images by type and priority (informative, functional, decorative, complex).
• Adopt alt-text templates for common image types and embed in CMS fields.
• Set CMS validation to require alt-text where appropriate and alt="" for decorative images.
• Deploy automated alt-text generation for initial drafts with confidence thresholds.
• Establish human-review queues for high-risk images and exceptions.
• Run monthly audits (coverage) and quarterly accessibility testing with real users.
• Monitor image search metrics in Search Console and iterate based on data.

FAQ

How long should alt-text be?

Keep simple image alt-text to roughly 5–15 words; use longer descriptions for complex images where required meaning needs more detail.

Should I include keywords in alt-text?

Only include keywords if they’re naturally relevant to the image’s content or purpose; never add them in a way that reduces clarity for assistive users.

When should I use alt=""?

Use alt="" for purely decorative images that add no informational value so screen readers skip them.

Can I rely solely on automated alt-text?

No—automation is useful for scale, but human review is necessary for accuracy, context, and sensitive content.

How do I handle images with lots of text (e.g., screenshots)?

Provide a concise summary in alt-text and include a longer transcript or textual equivalent nearby or via an accessible link.