Writing Accessible Alt Text for Images

Writing alt text is a simple way to make your site more accessible and easier to navigate, but there are a few need-to-knows to be able to write alt text that’s useful and provides the information and context needed.

Firstly, alt text isn’t required, and shouldn’t be used, for every image. In fact, this can actually make it more of a nuisance or make it harder to navigate the page. Instead, one should focus on using alt text for important images where the description would add value or context to the content.

The ideal length for alt text is about 125 characters at most, or around 1-2 sentences. They aren’t designed to give a user the “play-by-play” of what’s going on in the image, but just enough information for them to understand the intention or added context of the image. As a note, alt text shouldn’t start off with a phrase such as “an image/photo of…” and instead should simply describe the contents of the image.

For example, from the NTD Champion’s page on The END Fund’s site, this image has the alt text of ‘Three women filling out paperwork. A donation to help end neglected tropical diseases goes to people like them.’

This alt text not only gives context for the photo and the idea of it for those who are using screenreaders, but acts as a call to action as well, adding context surrounding the organization’s mission and their impact on the communities they serve.

As a note, alt text shouldn’t start off with a phrase such as “an image/photo of…” and instead should simply describe the contents of the image.

In addition to alt text, you should always provide closed captions and transcripts for multimedia content. These captions and/or transcripts should also be accurate and easy to navigate.

Overall, writing alt text requires an understanding of the context of the content around the image as well as the context and information the image is designed to give, and melding those together. They’re meant to serve as a way for those using screen readers or other accessible technology to properly navigate your site and get the information they need.

Image Types

Alt text and its implementation also depends on the particular types of images the site is using, such as icons, links, and graphs.

Icons and Links

For icons, such as buttons for your social media, the alt text should describe the action or the information intended. This can also include the ‘skip to bottom’ or ‘back to top’ icons. Link alt text should describe what will happen when the link is clicked, such as going to a certain page. This can be phrased as ‘[Your Organization] homepage, link.’

This link to Tony La Russa’s Animal Rescue Foundation might use the alt text, ‘ARF Instagram page, link’ to indicate that this social media icon goes to their instagram page. 


Graphs are a more intricate topic, as it depends on their complexity. In the case of simpler graphs, it’s best to provide a concise message on the data or information displayed. For more complex graphs, special care should be taken to convey the information including categories, trends, & minimum & maximum values. The user should be able to get the idea of the point of the graph without having an overly long alt text explanation.

As a last example, if your nonprofit posted a bar graph similar to this, you’d want your alt text to explain the context behind the categories and the information you’re comparing. For instance, it may read something like ‘This chart shows the amount of people our organization has helped by age. It shows that Category A, those 50-65, are the population most helped by our work.’

Images of Text

When text is in an image, it limits a person’s ability to change or customize the displaying of the text. In this case, the alt text can use the words in the image itself.

Alt Text on Various Platforms

Various platforms have different ways of adding and displaying alt text, which you’ll need to know about. This includes PDFs, Word and other Microsoft documents, Google Docs, and social media platforms. Adding alt text when you’re working with various types of documents and posts will help make sure that your posts are accessible across all channels, not just on your site.

Doing so, especially on social media, helps your engagement and makes sure that you’re able to promote your nonprofit to potential volunteers and donors, as well as those who may benefit from your programs. 

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