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.
The terms “alt text” and “image description” are often used interchangeably, but they are in fact different.
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.
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.
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.
Questions people often ask about creating accessible images and visuals.
Question: If a platform has AI-generated image descriptions, is it okay to rely on those instead of writing custom image descriptions?
Answer: No. 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.
Question: Is it better to use a platform’s designated alt text field or write a visible image description in the body of a post?
Answer: If you want to make your post fully accessible, you should actually do both, believe it or not. Not everyone who needs access to textual information about the details of an image uses assistive technology, so by writing alt text and an image description, you’re covering all your bases. Some folks will duplicate their alt text and image description, while others will try to indicate in the alt text field that an image description can be found in the body of the post. It’s up to you how you choose to proceed.
Twitter and BlueSky are the only platforms where you don’t need to implement this practice because they both have a visible alt text badge. Just make sure to write descriptive alt text.
Question: Is there a way to view the alt text written for images on other websites besides social media?
Answer: Yes. If you have a smartphone, use the text-to-speech program built into it. The text-to-speech program on iPhone is called VoiceOver. On Android devices, it’s usually called TalkBack. Once you activate the text-to-speech program, you can tap an image to hear the alt text read aloud.
You can also use Google Chrome on your desktop. Right click on an image, select “Inspect,” and then there should be a tab labeled “Accessibility” in the panel that pops up to the right. Click that tab. Once you’re in the Accessibility tab, you’ll see an accessibility tree. If the image had alt text applied to it, it’ll be at the very bottom of the tree. It will also be in the area labeled “Name” below the accessibility tree. If it’s cut off by the panel, just hover over it to read the alt text.