Intro

title: "Accessible Images Intro — Why Images Must Be Accessible" description: "Learn why image accessibility is critical for users who cannot see images and how proper alt text, descriptions, and ARIA make images inclusive." weight: 1 date: 2026-06-28 lastmod: 2026-06-28 tags: [accessibility, images]

Accessible images provide text alternatives that convey the same information to users who cannot see the image, using alt text, descriptions, and ARIA attributes.

## What You'll Learn

Why image accessibility matters, the different types of images, and WCAG criteria that apply to non-text content.

## Why It Matters

Images convey information, emotions, and context. Without text alternatives, users with visual impairments miss content that sighted users take for granted.

## Real-World Use

A blind user visits a news article with an infographic about climate change. The alt text describes the key data points and trends shown in the image, allowing the user to understand the information.

## Image Accessibility Rules

```mermaid
flowchart LR
  A[Meaningful Image] --> B[Descriptive alt text]
  C[Decorative Image] --> D[Empty alt text]
  E[Functional Image] --> F[Alt describes action]
  G[Complex Image] --> H[Long description]

Common Mistakes

1. Missing alt attribute

Images without alt attributes are announced with the file name or "image" with no description.

2. Redundant alt text

Alt text that repeats nearby text is unnecessary. Leave empty alt for decorative images.

3. Alt text too long

Alt text should be concise. Use longdesc or aria-describedby for detailed descriptions.

4. Keyword stuffing in alt text

Alt text should describe the image, not stuff keywords for SEO.

5. Decorative images not hidden

Decorative images need alt="" (empty alt) to be hidden from screen readers.

Practice Questions

1. What HTML attribute provides a text alternative for images? The alt attribute on the img element provides the text alternative.

2. How do you mark an image as decorative? Set alt="" (empty alt) to tell screen readers to ignore the image.

3. What is the maximum recommended length for alt text? Around 125-150 characters for standard alt text. Use long descriptions for complex images.

Challenge: Navigate a news website with a screen reader. Count how many images have missing, adequate, or missing alt text.

FAQ

Mini Project

Audit 10 images on a website. For each, determine if it is meaningful or decorative, and write appropriate alt text. Check that decorative images have empty alt.

What's Next

Learn Alt Text Basics and how to write effective alternative text for different image types.