2026-05-17 · 7 min read

WCAG Alt Text for Government Websites: What 1.1.1 Requires for Each Image Type

# WCAG Alt Text for Government Websites: What 1.1.1 Requires for Each Image Type

Missing alternative text is detected on more than half of all websites tested in the WebAIM Million report — year after year, at roughly the same rate. Government sites are no exception, and in some ways they have a harder alt text problem than most.

The volume of images on a typical government site is substantial: staff directory headshots, event photos, ribbon-cutting photos, ordinance documents with embedded images, GIS maps, budget infographics, organizational charts, government seal logos, and department logos scattered across every page. Each image type has a different requirement under WCAG 1.1.1.

This post explains what the criterion requires for each type, why government alt text commonly fails, and how to write alt text that communicates rather than just satisfies a checkbox.

What WCAG 1.1.1 Actually Requires

The criterion is: "All non-text content that is presented to the user has a text alternative that serves the equivalent purpose."

The key phrase is "equivalent purpose." Not "a description of the image." Not "what the image looks like." The text alternative must communicate whatever information the image communicates to a sighted user.

This means the requirement changes depending on what the image does. A staff headshot communicates "this is what this person looks like" — the alt text doesn't need to describe their appearance in detail, but it should identify the person. A budget infographic communicates specific data — the alt text must convey that data, not just say "budget chart."

The Six Image Types on Government Sites

1. Informational images

These images convey information that isn't available elsewhere on the page.

Examples on government sites:

• Event photos (ribbon cutting, city council meeting photo)
• Press release images
• Construction or project progress photos
• Condition documentation photos (road damage, facility status)

What the alt text must do: Communicate the essential information the image provides. For an event photo: "Mayor Jones and Council Member Smith cut the ribbon at the opening of Riverside Park's new splash pad, July 4, 2026." The alt text doesn't describe every detail — it conveys what the photo means in context.

What government sites commonly do instead: alt="IMG_20260704_142233.jpg" (the file name), alt="photo", alt="event photo", or no alt attribute at all.

2. Decorative images

Images that are purely decorative — they exist for visual interest but add no information.

Examples on government sites:

• Section dividers styled as decorative wave or line graphics
• Abstract background images on hero banners where the text on top is the content
• Repeated logo watermarks in document backgrounds
• Decorative icon graphics that accompany labeled text

What the alt text must be: An empty alt attribute: alt="". This is mandatory, not optional. An empty alt tells screen readers to skip the image entirely. Without it, screen readers announce the file name or "image" — which creates noise without information.

The failure pattern: Many government CMS systems automatically populate alt text with the file name when it's left blank. The CMS behavior produces alt="decoration-wave-blue.svg" instead of alt="". This is technically worse than no alt attribute for decorative images.

3. Functional images

Images that act as buttons, links, or controls — images that do something when activated.

Examples on government sites:

• Logo images that are links to the homepage
• Search buttons styled with a magnifying glass icon
• Social media icons that link to social accounts
• Print, download, or share icons

What the alt text must describe: The function, not the appearance. The alt text on the logo-as-homepage-link should be the agency name: alt="City of Tallahassee — Home" — not alt="city logo". The magnifying glass search button should be alt="Search" — not alt="magnifying glass icon".

The failure pattern: alt="logo.png" or alt="twitter" (the brand name, not the function). Or worse, alt="" on functional images — which makes them invisible to screen readers and keyboard users who rely on the accessible name to understand what the control does.

4. Complex images — charts, graphs, infographics

Images that contain substantial data or multi-part information that cannot fit in a short alt text.

Examples on government sites:

• Budget allocation pie charts
• Population trend line graphs
• Organizational hierarchy charts
• Infrastructure maps with data layers
• Project timelines displayed as infographics

What the requirement demands: Two-part treatment: 1. A short alt text describing the image and its purpose (e.g., alt="Bar chart showing departmental budget allocations for fiscal year 2026") 2. A longer description providing the actual data or information — either in adjacent page text, in a data table below the chart, via a link to a data table, or using aria-describedby to point to a detailed description element

If the chart shows that Public Works received 34% of the budget and Parks received 12%, that data must be available in text form somewhere — in the alt attribute itself (if the data is brief) or in a linked or adjacent data representation.

The failure pattern: alt="FY2026 Budget Chart" with no data accessible in text form. The chart label communicates what the chart is about but not what it shows. A screen reader user learns a chart exists and nothing about what it contains.

5. Images of text

Images that contain text as the primary content — often legacy content that was rendered as an image instead of real text.

Examples on government sites:

• Old meeting notices or announcements created in Word and saved as screenshots
• Flyers designed in image editing software where all text is part of the image
• Scanned forms or certificates
• Social media announcement graphics

What the alt text must include: The text in the image, verbatim or as complete as practicable. If the image is a notice saying "NOTICE: The December 15 Council Meeting has been cancelled," the alt text should be: alt="NOTICE: The December 15 Council Meeting has been cancelled".

The failure pattern: alt="December council meeting notice" — which summarizes the image rather than providing its content. A screen reader user learns a notice exists but not what the notice says.

6. Maps

Geographic maps present alt text challenges because they can be purely presentational (showing general location context) or data-heavy (showing specific geographic information critical to the content).

Examples on government sites:

• Embedded Google Maps showing office location (presentational)
• Zoning maps showing land use designations (data-heavy)
• Emergency evacuation zone maps (critical information)
• Infrastructure project location maps (informational)

For presentational maps: A short alt text identifying the map's purpose suffices: alt="Map showing the location of City Hall at 300 S Adams Street, Tallahassee, FL" — possibly with a link to Google Maps for more detail.

For data-heavy maps: Like complex charts, a short alt text plus an adjacent text description of the critical information. A zoning map with specific land use designations needs those designations available in a text table or list, not just in the image.

Alt Text for Government Images in PDFs

Everything above applies to images in PDFs too. The implementation is different (PDF tags instead of HTML attributes), but the requirements are identical. A staff photo in a PDF annual report needs alt text identifying the person. A budget chart in a PDF needs a text description of the data.

This is where government sites most commonly fail at scale: thousands of legacy PDFs with untagged images, images of text, and charts with no text descriptions.

Writing Alt Text That Works

The test: Read only the alt text. Does it give you the same information the sighted person gets from the image? If yes, it's working. If not, revise.

For informational images: Who, what, where — identify the people, action, and context that matter.

For functional images: Describe what happens, not what it looks like.

For complex images: What is the key finding or data the image communicates? Lead with that.

For decorative images: alt="". Always. No exceptions.

Never: File names, "image of," "picture of," "graphic of," or the word "photo" as the entire alt text.

The Parallax WCAG audit from Morton Technology Consulting includes a complete image accessibility review — covering all image types, PDF image treatment, functional image alt text, and complex image description completeness — as part of the 200-page site assessment.

The WCAG Pre-Audit Readiness Kit ($149) includes an alt text audit template covering all six image types, a decision tree for determining the correct alt text approach, and a CMS workflow checklist for ensuring new images are published with correct alt text.

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*Morton Technology Consulting LLC, Tallahassee, FL. WCAG 2.1 alt text and image accessibility audits for Florida government websites. [email protected]*

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