Introduction to Image Accessibility

Images play a key part in digital storytelling, marketing, and social media. But how does someone with a serious vision disability or individuals who use assistive technology experience a picture online?

Assistive devices and programs need textual information that provides a descriptive summary of an image’s key visual details. This can be done through alternative text—more commonly known as alt text—or image descriptions.

In addition to making an image accessible, alt text and image descriptions can impact legal compliance. In many countries, including the United States, there are laws and regulations that require digital content to be accessible to people with disabilities. Failure to comply with these regulations can result in legal penalties, revenue loss, and negative publicity for brands and organizations.

Making digital images accessible can benefit your search engine optimization (SEO) strategy as well. Search engines like Google use alt text and other metadata to understand the content of images and rank webpages in search results. By providing accurate and detailed image descriptions, webpages can improve their visibility and search engine ranking.

Alt Text vs. Image Descriptions

The terms “alt text” and “image description” are often used interchangeably, but they are in fact different.

  • Alt text: a short, concise text description of an image. However, you can make it longer if you want it to be more descriptive. It’s added to an image tag in the HTML code of a webpage or through a platform’s designated alt text field. While normally brief, alt text should still accurately convey the content and function of an image. It’s also commonly referred to as an “alt tag” or “alt attribute” when used in web development projects.
  • Image description: a more detailed description of an image and it’s provided in the content of the webpage, typically near the image or as a visible caption. On a social media platform, it would be in the body of your post.

The purpose of an image description is to provide additional context and information about a visual, beyond what can be conveyed in short alt text. Image descriptions may include details such as the colors, shapes, sizes, textures, and other elements in an image, as well as its context and meaning.

In short, you should think of an image description as a more robust version of alt text. It gives additional details to create a more informative description of an image and is normally preferred to alt text when it comes to accessibility.

Let’s use the below image as an example. The alt text and image description for it would be very different.

  • Alt Text: Pancakes
  • Image Description: A stack of pancakes covered in gooey syrup, powdered sugar, and fresh fruit on a white ceramic plate.
A stack of pancakes covered in gooey syrup, powdered sugar, and fresh fruit on a white ceramic plate.
Photo Credit: Ash Craig via Pexels

Which one made your stomach growl? More importantly, which one painted a more detailed visual in your mind? The alt text gets the job done on a technical level, but the image description provided more information about the picture and made it more accessible.

To be clear, it doesn't necessarily matter if you say "alt text" or "image description" as long as you're making your visuals accessible. That is what's most important.

AI-Generated Image Descriptions

You should never rely on auto-generated image descriptions that have been written by an artificial intelligence (AI) program.

Platforms like Facebook, Instagram, and Threads will often tout their AI-generated image descriptions as a reliable substitute for not writing custom image descriptions or making an alt text field available. However, AI-generated image descriptions aren't normally very descriptive or accurate enough to be considered accessible and will lack important context. They usually just sound like a string of random keywords, as demonstrated in the below video.

Frequently Asked Questions

Questions people often ask about creating accessible images and visuals.

Question: Are there any examples of image descriptions on Accessible Social?

Answer: Yes! You'll find sample social media scenarios paired with images on our Accessible Image Scenarios page. Each visual has an example image description written for it.

Question: Can you mark images on social media as decorative?

Answer: In the traditional web development sense, no, you cannot mark visuals you upload on social media as decorative images. Even without this functionality, the argument could be made that there are very few instances where an image on social media would be considered decorative. Social media content is normally about telling a story in an abbreviated fashion through short copy and eye-catching visuals. If you upload an image to accompany a post, it more than likely has context that viewers should know about, even if it feels minor. You should always write detailed image descriptions for your social media images and never just write "null" or "decorative" in a designated alt text field.

Question: I want to retweet something, but the image doesn’t have alt text. What’s the best way to add it?

Answer: If you're going to retweet a piece of content that doesn't have alt text, quote retweet it and write a description for the image in your tweet. Just make sure that you precede your alt text with the words "image description" or "alt text" so it's clear to a screen reader user what you're tweeting about.

Additional Resources and Reading

Want to learn a little more about creating accessible images and visuals? Check out the links below!