Structural Design

Alternative Text

Text that provides a meaningful alternative for images or non-text content when visual access is unavailable or insufficient.

Concept facts

Alternative text is text that communicates the purpose or meaning of an image or non-text element when the visual content cannot be seen, loaded, or understood.

Also known as
Alt text, text alternative, image description, non-text alternative
Used in
Web accessibility, digital content, public-service pages, learning materials, forms, charts, document uploads, social media accessibility
Interpret with
Image purpose, surrounding content, task context, user need, decorative status, complexity, assistive technology, and accessibility requirements

Plain-language explanation

Alternative text helps users understand non-text content when they cannot see it or when the image does not load. It is commonly used for images, icons, charts, diagrams, buttons, and other visual content.

Good alternative text is not always a literal description of every visual detail. It should communicate the meaning or function of the image in context.

For example, an image used as decoration may need empty alternative text. A chart showing benefit eligibility thresholds may need a concise summary and possibly a longer explanation nearby.

Why it matters

Important information is often placed inside images, scanned documents, icons, infographics, or charts. Without a text alternative, screen reader users, low-vision users, people with poor connectivity, and users relying on text extraction may miss critical information.

In institutional systems, missing or poor alternative text can prevent users from understanding deadlines, requirements, warnings, form status, evidence instructions, or learning content.

Alternative text also supports search, content resilience, and access under low-bandwidth conditions.

Use contexts

  • Public-service content
  • Learning materials and course pages
  • Document and evidence instructions
  • Charts, diagrams, and infographics
  • Icons and image buttons
  • Social media and campaign content
  • Accessibility QA and content governance

Application guidance

Decide what the image is doing in context. If it conveys information, provide a meaningful text alternative. If it is decorative, use the correct empty alternative so assistive technologies can skip it.

For complex visuals, do not overload the alt attribute with long text. Provide a short alternative and a nearby detailed explanation, table, or transcript where needed.

Avoid generic text such as “image” or “graphic.” Alternative text should support the user’s task and understanding.

Practical example

A public benefits page includes an infographic showing income thresholds, household categories, and required documents. The page visually appears clear, but the image has alt text that says only “benefit chart.”

Screen reader users cannot access the eligibility rules. A better approach provides concise alternative text, a structured text summary, and an accessible table containing the same threshold and document information.

Interpretive boundaries

  • Alternative text is not always a visual description.
  • Decorative images may need empty alternative text.
  • Complex charts and diagrams may require more than an alt attribute.
  • Alternative text should be written for the image’s purpose in context.
  • Automated tools cannot fully judge whether alternative text is meaningful.

Applied at Userhub

Alternative text is relevant when Userhub evaluates accessibility, content clarity, learning materials, public-service pages, campaign assets, and digital documents that include meaningful non-text content.

See Userhub UX Lab for applied UX research and evaluation context.

Sources and references

  • W3C. (2023). Web Content Accessibility Guidelines (WCAG) 2.2. W3C Recommendation. https://www.w3.org/TR/WCAG22/
  • ISO/IEC. (2012). Information technology — W3C Web Content Accessibility Guidelines (WCAG) 2.0 (ISO/IEC Standard No. 40500:2012). International Organization for Standardization.
  • W3C Web Accessibility Initiative. (2024). Images Tutorial. W3C. https://www.w3.org/WAI/tutorials/images/
  • Bigham, J. P., Kaminsky, R. S., Ladner, R. E., Danielsson, O. M., & Hempton, G. L. (2006). WebInSight: Making web images accessible. Proceedings of the 8th International ACM SIGACCESS Conference on Computers and Accessibility, 181–188. https://doi.org/10.1145/1168987.1169018

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Cite this entry

APA

Userhub. (2026). Alternative Text. UX Reference. https://userhub.com.bd/reference/alternative-text/