What Is Image Accessibility?
Image accessibility refers to the practice of making non-text content, especially images, understandable to all users, including those using screen readers or with visual impairments. It primarily involves adding alt text (alternative text) that describes the purpose or content of the image.
Example:
<img src="award-ceremony.jpg" alt="Team receiving a web accessibility award on stage">
Without proper image accessibility, screen reader users miss crucial context, while others may struggle with unclear or nonfunctional content.
Why Image Accessibility Matters
Images play a key role in web communication, from product photos to infographics, but without accessible descriptions, they're a barrier. That's why WCAG (Web Content Accessibility Guidelines) and laws like the ADA (U.S.) and BFSG (Germany) require that all informative visual content is perceivable by assistive technology.
Image accessibility is not optional, it’s essential for meeting accessibility compliance, enabling digital inclusion, and improving user experience.
Types of Images and How to Handle Them
Understanding the purpose of an image helps determine how to describe it—or whether to describe it at all:
1. Informative Images
These convey essential content.
➡️ Example: A graph showing website traffic trends.
✅ Use meaningful alt text:
alt="Line chart showing an increase in traffic from January to March"
2. Decorative Images
Purely for aesthetics, these should be ignored by screen readers.
✅ Use alt="" and mark with aria-hidden="true" if needed.
3. Functional Images
These act as buttons or links.
✅ Alt text should describe the function, not appearance:
alt="Download PDF brochure"
4. Complex Images (Infographics, Charts)
Require a detailed description elsewhere on the page or in a linked file.
✅ Alt text:
alt="Infographic summarizing web accessibility statistics. Full text below."
Accessible Galleries and Carousels
Image sliders and galleries often fail accessibility checks. Here's how to fix that:
- ✅ Ensure all images have alt text.
- ✅ Use clear keyboard controls (Tab, Arrow keys) to navigate slides.
- ✅ Label carousel buttons (e.g., aria-label="Next Slide").
- ✅ Indicate current slide with aria-current.
TYPO3 Tip: Use accessible image and gallery elements in content blocks or with extensions like Accesstive.
WordPress Tip: Use accessibility-ready themes and check alt text in your media library. Plugins like “FooGallery” offer accessibility settings.
Common Mistakes & Misconceptions
❌ “Alt text isn’t needed for logos or icons.”
✔️ Logos and icons with meaning must be described. Use alt="Company logo" or alt="Search icon".
❌ “Placeholders are enough for accessibility.”
✔️ Placeholder text does not replace proper alt text—it’s often invisible to screen readers.
❌ “Just describe every image in detail.”
✔️ Not all images need full descriptions—context and function determine the right level of detail.
Explore related terms: Alt Text, ARIA, Web Accessibility, Screen Reader, WCAG
Key Takeaway
Every image tells a story, but not every user can see it.
Image accessibility ensures that everyone, regardless of ability, can understand and interact with visual content. It’s a vital step toward inclusive, accessible websites.
Want to Make Your Visual Content More Inclusive?
Use the T3AA Accessibility Analyzer to scan for missing alt text, or download our Image Accessibility Checklist.
Design visually. Describe accessibility. Build inclusively.