Alt Text and Long Descriptions

What it is

Alternative text (alt text) and long descriptions are textual alternatives to visual content in Word documents. They make images, charts, diagrams, and other non-text content accessible to people who cannot see them.

Alternative text (alt text)

Alt text is a brief description of an image that:

  • Conveys the essential information or function of the image
  • Is typically 1-2 sentences (up to 125 characters is ideal)
  • Is read aloud by screen readers in place of the image
  • Appears if the image fails to load

Long descriptions

Long descriptions provide detailed explanations for complex images that:

  • Contain significant detail that cannot be summarized briefly
  • Include data visualizations, charts, graphs, diagrams, or flowcharts
  • Require more than 125 characters to describe adequately
  • May be provided in the document body, a caption, or an appendix

Decorative images

Some images are purely decorative and don't convey meaningful information. These should be marked as decorative so screen readers skip them entirely.

Why it matters

Providing text alternatives for images is essential for several reasons:

  • Screen reader users: People who are blind or have low vision rely on screen readers that cannot interpret images without text descriptions
  • Context and meaning: Alt text ensures everyone understands the purpose and content of images, regardless of whether they can see them
  • Technical issues: If images fail to load or display, alt text provides the essential information
  • Search and navigation: Alt text makes images searchable and helps users understand document content
  • Legal compliance: Accessible documents with proper alt text meet WCAG 2.1 Level AA requirements and legal obligations
  • PDF conversion: Alt text added in Word carries over to PDF documents, maintaining accessibility

❌ Without alt text

A screen reader encountering an image without alt text will either skip it entirely or announce unhelpful information like "Image" or the file name "IMG_20231015_142304.jpg", leaving the user with no understanding of the image's content or purpose.

How to do it

Adding alt text in Word

Method 1: Using the Alt Text pane (recommended)

  1. Right-click on the image
  2. Select View Alt Text from the contextual menu
  3. The Alt Text pane opens on the right side of the screen
  4. Type your description in the text box:
    • Describe what the image shows and its purpose
    • Be concise but complete
    • Include relevant text that appears in the image
    • Aim for 125 characters or less when possible
  5. If the image is decorative, check the "Mark as decorative" checkbox instead of adding description text

Method 2: Using the Format Picture dialog

  1. Right-click on the image
  2. Select Format Picture
  3. In the Format Picture pane, click the Size & Properties icon (looks like a square with arrows)
  4. Expand the Alt Text section
  5. Enter your description in the Description field
  6. Note: The Title field is optional and not always read by screen readers

Method 3: Using the ribbon

  1. Select the image
  2. Go to the Picture Format or Picture Tools Format tab
  3. Click Alt Text in the Accessibility group
  4. The Alt Text pane opens; add your description

Writing effective alt text

General principles

  • Be accurate: Describe what is actually in the image
  • Be concise: Focus on essential information; aim for 125 characters or less
  • Be specific: Provide meaningful detail rather than generic descriptions
  • Avoid redundancy: Don't start with "Image of..." or "Picture of..." - screen readers announce it's an image
  • Include text: If the image contains important text, include it in the alt text
  • Convey function: If the image is a button or link, describe what happens when clicked

Examples of good alt text

Photo of people in a meeting:

  • ❌ Poor: "Meeting"
  • ❌ Poor: "Image of people"
  • ✅ Good: "Five team members reviewing project plans around a conference table"

Logo:

  • ❌ Poor: "Logo"
  • ✅ Good: "ESDC IT Accessibility Office logo"

Screenshot showing a button:

  • ❌ Poor: "Screenshot"
  • ✅ Good: "Screenshot of the Save button in the Word toolbar, showing a blue disk icon"

Decorative image:

  • ❌ Poor: "Blue swirl decoration"
  • ✅ Good: Mark as decorative (no alt text needed)

Context matters

The same image may need different alt text depending on context:

  • In an article about dogs: "Golden retriever sitting in a park"
  • In a photo editing tutorial: "Photo with high contrast and warm color temperature"
  • On a pet adoption page: "Max, 3-year-old golden retriever available for adoption"

Creating long descriptions

When to use long descriptions

Use long descriptions when:

  • The image contains complex data (charts, graphs, diagrams)
  • The image includes multiple important elements that each need description
  • The image conveys a process or relationship that requires explanation
  • A brief alt text would not adequately convey the image's information

Methods for providing long descriptions

Method 1: In the document body (recommended)

  • Place detailed description in the paragraph immediately before or after the image
  • Keep alt text brief: "Bar chart showing quarterly sales data (see description below)"
  • Begin the paragraph with: "Description of chart:" or similar indicator
  • This approach ensures all users benefit from the detailed description

Method 2: In a caption

  • Use Word's caption feature: Right-click image > Insert Caption
  • Include the description in the caption text
  • Keep alt text brief: "Organizational hierarchy chart (see caption for details)"

Method 3: In an appendix

  • For documents with many complex images
  • Create an appendix titled "Image Descriptions" or "Extended Descriptions"
  • Number images and descriptions
  • In alt text, reference the appendix: "Flowchart of approval process (see Appendix A, Figure 3 for detailed description)"

Writing long descriptions

For charts and graphs, describe:

  • The type of chart (bar, line, pie, etc.)
  • What data is being shown
  • Key trends or patterns
  • Notable data points (highest, lowest, anomalies)
  • The overall conclusion or takeaway

Example: Bar chart description

Brief alt text: "Bar chart showing quarterly sales 2023 (see description below)"

Long description in body text:

"Description of chart: This bar chart displays quarterly sales figures for 2023. Q1 shows $2.5M, Q2 shows $3.1M, Q3 shows $2.8M, and Q4 shows $3.4M. The data reveals a general upward trend with a slight dip in Q3. Q4 represents the highest sales quarter, showing a 21% increase over Q1."

Marking decorative images

What are decorative images?

Decorative images are visual elements that:

  • Don't convey information necessary to understand the content
  • Are used purely for visual design or aesthetics
  • Would not cause confusion if removed
  • Examples: borders, dividers, background patterns, purely aesthetic photos

How to mark as decorative

  1. Right-click on the image
  2. Select View Alt Text
  3. Check the "Mark as decorative" checkbox
  4. Screen readers will skip this image entirely

⚠️ When in doubt

If you're unsure whether an image is decorative, it's better to provide alt text. An extra description is better than missing information. Ask yourself: "Would someone miss important information if they couldn't see this image?" If yes, it needs alt text.

Special cases

Complex diagrams

For complex diagrams, flowcharts, or organizational charts:

  • Brief alt text: Identify the type and topic
  • Long description: Describe the flow, relationships, and key elements
  • Consider creating a text-based table as an alternative representation

Screenshots with text

For screenshots that include visible text:

  • Include all visible text in the alt text or description
  • Describe the context and what the screenshot shows
  • Example: "Screenshot of Word's Home tab showing the Styles group with Heading 1, Heading 2, and Normal styles visible"

Infographics

For infographics combining text and images:

  • Brief alt text: Topic and type
  • Long description: Include all text and describe visual relationships
  • Consider providing data in an accessible table as an alternative

Linked images

If an image is a hyperlink:

  • Alt text should describe the link destination or action
  • Example: "Go to accessibility resources page" (not just "Arrow icon")
  • Include both image content and link purpose if both are important

Checking your work

Use the Accessibility Checker

  1. Go to Review > Check Accessibility
  2. The Accessibility Checker will flag images without alt text
  3. Click on each issue to jump to that image
  4. Add alt text or mark as decorative as appropriate

Review all images systematically

  • Go through your document page by page
  • Right-click each image and check View Alt Text
  • Verify alt text is meaningful and adequate
  • Ensure decorative images are marked as such

✅ Alt text and descriptions checklist

  • ☐ Every informative image has alt text
  • ☐ Alt text is concise (ideally under 125 characters)
  • ☐ Alt text is accurate and describes essential information
  • ☐ Alt text doesn't start with "Image of" or "Picture of"
  • ☐ Text visible in images is included in alt text
  • ☐ Complex images have long descriptions provided
  • ☐ Long descriptions are in body text, captions, or appendix
  • ☐ Decorative images are marked as decorative
  • ☐ Linked images describe the link destination
  • ☐ Accessibility Checker shows no missing alt text errors
  • ☐ Alt text provides equivalent information to visual content