In today’s digital ecosystem, images play a central role in storytelling, branding, and conversions. However, without meaningful alternative (alt) text, those visuals become invisible to millions of assistive technologies’ users. Alt text is not just a technical checkbox - it is a foundational accessibility requirement and a powerful contributor to SEO when implemented correctly.
This article explores the role of image alt text in accessibility.
What is alt text, and why does it matter?
Alt text is a short-written description added to an image’s HTML alt attribute. It serves two primary purposes:
- Accessibility: It allows screen readers to describe images to users with visual impairments. Screen readers such as JAWS, NVDA, and VoiceOver rely on alt text to communicate visual content.
- Fallback Content: It appears if an image fails to load due to slow connectivity or technical errors.
Under global accessibility standards like Web Content Accessibility Guidelines (WCAG), providing text alternatives for non-text content is a Level A requirement. This makes alt text legally and ethically essential for inclusive web design.
The accessibility role of alt text
- Equal access to information
Without alt text, a product image, infographic, or banner provides no meaningful information to someone using a screen reader. Proper alt text ensures that users receive the same context and content as sighted users.
- Functional clarity
If an image acts as a button or link, its alt text must describe the function – not just the appearance.
For example:
a. “Shopping cart icon” – wrong text.
b. “View shopping cart” – right text.
The second example explains the action, which is what matters for accessibility.
- Contextual understanding
Alt text helps users understand charts, diagrams, and promotional visuals when they cannot see them. For complex visuals, alt text may need to be paired with extended descriptions.
Best practices for writing effective alt text
- Be descriptive but concise
Aim for clarity within 125 characters when possible. Screen readers may pause or truncate long descriptions.
Example:
a. “Image” – wrong text
b. “Picture of a man” – wrong text
c. “User browses an ecommerce website” – right text.
- Focus on meaning, not every detail
Describe what is important in context.
If an article is about remote work accessibility:
a. “Employee attending virtual meetings” - right text.
b. “Woman with brown hair wearing glasses sitting at a wooden desk with a blue mug” - wrong text.
- Avoid redundant phrases
Screen readers already announce the content as an image. Avoid starting with:
a. “Image of ….”
b. “Picture of ….”
Unless context requires it (for example, distinguishing between a logo and an illustration).
- Use empty alt text for decorative images
Decorative images that add no informational value should use:
</> HTML
alt=””
This prevents screen readers from reading irrelevant content like “decorative swirl pattern”.
- Describe the function for linked images
If an image links to another page:
a. “Company logo” – wrong text.
b. “Visit homepage” – right text.
- Provide detailed descriptions for complex graphics
For charts and infographics:
a. Use concise alt text for a summary.
b. Provide a longer explanation in the surrounding content.
Example alt text:
“Bar chart showing 40% increase in website engagement after accessibility improvements”.
Then include a detailed breakdown in the article body.
- Keep context in mind
The same image may require different alt text depending on the page.
For example, a product image:
a. On a category page: “Red cotton summer dress”.
b. On a product page: “Front view of red cotton summer dress”.
Common alt text mistakes to avoid
- Keyword stuffing for SEO.
- Using file names like “IMG_4589.jpg”.
- Leaving important images without alt attributes.
- Repeating adjacent captions word-for-word.
- Over-describing purely decorative images.
Alt text and SEO: how they work together
Alt text improves SEO, but only when written naturally and meaningfully.
Search engines such as Google use alt text to understand image content and context. Well-written alt attributes can:
- Improve image search rankings.
- Support page topic relevance.
- Enhance overall accessibility (which contributes to better user experience signals).
Why does accessibility improve SEO?
- Improved user experience: Lower bounce rates and higher engagement.
- Better content indexing: Search engines understand visual content more accurately.
- Mobile optimization: Text alternatives support performance in low-bandwidth conditions.
- Inclusive reach: Accessible websites serve wider audiences, increasing potential traffic.
However, SEO should never compromise accessibility. The primary goal of alt text is to support users - SEO benefits follow naturally from good accessibility practices.
Practical examples across use cases
Ecommerce product image
Alt text:
“Black leather office chair with adjustable height and armrests”
Infographic
Alt text:
“Infographic of digital accessibility audit process”
Team member photo
Alt text:
“Headshot of customer support manager smiling”.
Logo
If used as a homepage link:
“Company name homepage”
If purely branding on a static page:
“Company name logo”
Accessibility standards and compliance
Providing alt text aligns with accessibility laws and standards worldwide. Under Web Content Accessibility Guidelines, Success Criterion 1.1.1 (Non-text Content) requires text alternatives for all meaningful non-text content.
Organizations that ignore this requirement risk:
- Legal complaints
- Loss of customers
- Damaged brand reputation
- Poor search performance
Alt text is often one of the first elements evaluated in manual accessibility audits.
How to audit alt text effectively?
- Use automated accessibility tools to detect missing alt attributes.
- Manually review descriptions for clarity and context.
- Test with screen readers to understand the real user experience.
- Check for decorative image handling using empty alt attributes.
- Ensure consistency across CMS templates.
Accessibility is not just about adding alt text - it’s about adding the right alt text.
Future trends: AI and alt text
AI-powered tools can now generate alt text automatically. While helpful for large image libraries, human review remains essential. AI may misinterpret context or produce vague descriptions.
A balanced approach - AI assistance with human oversight ensures both efficiency and inclusivity.
An AI accessibility widget like All in One Accessibility supports this balanced approach with AI-based image alt text remediation, helping websites quickly generate alternative text for images. The AI suggestions can streamline accessibility improvements across large volumes of visual content while allowing teams to review and refine descriptions for accuracy and context. This combination of AI assistance and human validation helps organizations improve accessibility, usability, and alignment with WCAG guidelines.
You may also like: Accessibility in AI Generated content
Wrapping up
Image alt text plays a critical role in digital accessibility and inclusive design. It enables screen reader users to understand visual content, supports legal compliance under WCAG, and contributes positively to SEO performance.
When written thoughtfully - descriptive, contextual, and purposeful alt text enhances user experience for everyone. Accessibility is not separate from SEO or usability; it strengthens both.
Ultimately, alt text is more than a technical attribute. It is a commitment to digital inclusion, ensuring that no user is excluded from experiencing the digital content.
At Skynet Technologies, we help businesses turn accessibility best practices – like meaningful alt text; into measurable compliance and SEO success. Our expert-led accessibility audits, accessibility remediation, ongoing monitoring and support enhance the usability of website for everyone. Reach out hello@skynettechnologies.com for more information.
