Issue 42

This issue checks whether all image elements (<img> tags) on a webpage include meaningful alternative (alt) text that describes the image content or purpose.

What passes

A passing implementation means that every meaningful image has descriptive alt text. This is considered passing when:

• All content images have an alt attribute present
• The alt text is descriptive and meaningful (not generic placeholders like "image" or "photo")
• Decorative images properly use empty alt text (alt="")
• At least 80% of images have descriptive alt text (when non-descriptive alt exists)

Example

An image tag written as <img src="golden-retriever.jpg" alt="Golden retriever playing in park with red ball"> would pass. However, <img src="img1.jpg" alt="image"> (generic alt) or <img src="photo.jpg"> (missing alt) would fail.

Alt text is critical for both accessibility and SEO:

Accessibility

Alt text enables screen readers to describe images to visually impaired users. Missing or poor alt text creates barriers to accessibility and may violate WCAG guidelines (a legal requirement in many jurisdictions).

Rankings & Indexability

Search engines use alt text to understand image content and context. Descriptive alt text helps images appear in image search results and provides semantic signals for page relevance.

AI Search / AEO

As AI-powered search systems become more prevalent, they rely heavily on alt text to understand visual content and answer image-related queries.

SEO Health Score Impact

Resolving this issue improves the overall SEO health score by ensuring the site meets accessibility standards and provides clear image context to search engines. Sites with proper alt text typically see better image search visibility and improved accessibility compliance.

1. Add alt text to all images

Ensure every meaningful image includes an alt attribute that describes what the image shows or represents.

2. Make alt text descriptive

Write alt text that conveys the purpose or content of the image, not just its appearance. For example, use "Woman using laptop to check email" instead of "laptop image".

3. Use empty alt for decorative images

For purely decorative images that don't convey meaning, use alt="" so screen readers skip them.

4. Enforce in CMS workflows

Configure your content management system to require alt text input when uploading images.

5. Validate and iterate

After making changes, re-crawl the site to confirm all images have appropriate alt text and generic placeholders have been replaced with descriptive text.

Example 1: Passing Implementation

Scenario: Product image with descriptive alt text

Passing state:

<img
  src="golden-retriever.jpg"
  alt="Golden retriever playing in park with red ball"
/>

Alt text describes the image content in a meaningful way.

Example 2: Failing Implementation - Missing Alt

Scenario: Image without alt attribute

Failing state:

<img src="img1.jpg" />

Missing alt attribute entirely. Screen readers cannot describe the image.

Example 3: Failing Implementation - Generic Alt

Scenario: Image with non-descriptive alt text

Failing state:

<img src="photo.jpg" alt="image" />

Alt text is present but generic. Doesn't provide meaningful description.

PixyScan identifies this issue through the following logical steps:

1. HTML Parsing

The crawler fetches the page and parses the raw HTML code (without executing JavaScript).

2. Image and Alt Extraction

PixyScan identifies all <img> elements and extracts their src, alt, and other relevant attributes.

3. Alt Text Classification

Each image is classified into one of these categories:

• Descriptive alt present: The alt attribute exists and contains meaningful descriptive text
• Empty alt: The alt attribute exists but is empty (alt=""), appropriate for decorative images
• Missing alt: The alt attribute is completely absent from the tag
• Non-descriptive alt: The alt attribute exists but contains generic placeholders like "image", "photo", or filename-only text

4. Coverage Calculation

PixyScan calculates the percentage of images that have descriptive alt text.

5. Issue Triggering

The issue is flagged when:

• Any image is missing the alt attribute entirely
• Images have non-descriptive alt text and descriptive alt ratio is below 80%
• Five or more images are missing alt text (considered severe)
• The overall alt text compliance fails accessibility standards