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Accessible Technology Initiative

What is Alternative Text?

Alternative text is a brief image description that allows users with visual impairments to understand what an image is about. When a visually impaired user encounters an image, their screen reader device will look for a provided alt text description to describe the image aloud.

It should be noted there are many different approaches to writing alt text descriptions. While approaches can vary, the consensus by most is that alt text descriptions should follow WCAG best practices to be considered accessible.

Best Practices

A user on a laptop is surrouned by various media icons for social media, web and email

This section includes best practices for writing alternative text descriptions including common questions when providing alt text.

Is Alternative Text Required?

Yes! Alt text is required in all digital spaces where images are being shared to other users. This is to ensure everyone can access a shared image - even if they are visually-impaired.

Digital spaces include but are not limited to:

  • Websites & webpages
  • Images shared on Social Media & Mobile Apps
  • Online articles and publications
  • Email messages
  • Digital documents
  • Blogs & Online Forums
  • Virtual Meeting Spaces such as: Teams, Zoom
  • Digital Online Services, such as: WarriorLife, StanTutor, myStanState, WarriorConnect, etc.

See the next sections below for tips on how to write alt text descriptions.

Tips for Writing Alt Text

Image alt text icon

Your image alt text descriptions should:

  1. Tell users what they are looking at
    Are we looking at person, place or thing? If so, explain to users who, or what the image is about.

  2. Stay brief
    Most agree that alt text should not exceed 130-150 characters in length since these descriptions are read aloud via a screen reader. Any longer, in length and alt text can easily become an earful to a listener.

  3. Not include the phrase "image of" - or similar phrases from alt text
    This is because screen readers announce once they have encountered an image. Otherwise, an image alt text will be redundantly read aloud with: "Image of. Image of....".

What details should be left out from alt text?

Alt text descriptions should stay focused on the subject at hand. Leave out any irrelevant details that don't add value or significance to the image. Unless a specific detail is relevant to the discussion, it should not be included.

Irrelevant details often include:

  • Hair color
  • Clothing & accessories
  • Eye color
  • Gender
  • Ethnicity / Race

What is the difference between alt text and a photo caption?

Image alt text is not the same as a photo caption.

Photo Captions

  • Are visible to all users
  • Are visible text placed beneath an image
  • Most often captions do not provide an image description

Alt Text

  • Not visible to sighted users
  • Are available mainly to users of screen reader & assistive technologies
  • Provide descriptive details about what the image contains or is about

Alt Text Examples

There are many types of images, each with their own unique ways to describe. Below are some notable image examples with alt text descriptions.

If an individual is the focal point of the image, you would provide their name (and last name, if known) as the alt text. 

Acceptable Alt Text Descriptions:

  • Alissa Lopez
  • Alissa Lopez, Interim Director for Scholarly Studies Program (more descriptive)
  • Alissa (if last name not provided)

 

If multiple subjects are featured  in the photo, alt text can get difficult. Generally, it is helpful (when known) to provide the amount of people in the group photos. However, for photos where there are many individuals, it is better to adapt the alt text to the occassion. See next example.

Acceptable Alt text descriptions:

  • Three students gathered at a bench near the Stockton Campus
  • Three students pose for a group photo near a bench

 

 

For photos where there is obviously many individuals in a photo, it is better to adjust the alt text wording accordingly. In this example, a "crowd" would be a more suitable word than group.

Acceptable Alt Text Descriptions:

  • A crowd of graduates celebrate at the Class of 2023 ceremony at Stanislaus State
  • Crowds of graduates cheer at the Class of 2023 ceremony at Stanislaus State
A crowd of graduate students from the Class of 2023 Commencement ceremonies at Stan State

 

 

 

Collage images are often a challenge to describe since its multiple images in a single image. Most collages, however, will often have a general theme or activity tied to them. Strive to provide a short description of what the collage is about.

In this example, it happens to be a collage featuring 9 students from the Scholarly Studies Program.

Acceptable Alt Text Description:

  • Collage featuring 9 students from the 2025 Scholarly Studies Program cohort
  • Collage of 9 students from the 2025 Scholarly Studies Program cohort

 

 

A pie chart is considered a complex image, which requires two steps:

  1. Provide an alt text that sums the main point conveyed by the pie chart. In this example, the pie charts explains the tuition payment flows in 2025.
    Alt text will say:
    • Pie chart detailing tuition payment flows in 2025. See webpage for its breakdown.
       
  2. Provide the data from the pie chart as plain text available on the webpage. This is because your alt text description instructs users to refer to the webpage for the information breakdown contained in the pie chart image.
    • Tuition Payment Flows in 2025:
      • State Grants - 25%
      • Scholarships - 12.5%
      • Private Loans 62.5%

 

 

Resources

Learn more about alternative text descriptions by visiting the resources below.

Articles

 

Videos

Updated: June 17, 2025