When people ask me if I have any tips for improving accessibility of social media posts, I like to ask them if they know how to add alt text on social media platforms. While a lot of people know how to add alt text on one or two platforms, the truth is that alt text has to be added manually across all social media platforms so that blind and visually impaired users can understand what is in an image. It only takes less than a minute to add alt text to social media posts, so it’s an easy way to ensure that audiences who use assistive technology are not excluded. Here are my tips for how to add alt text on social media for common platforms.
Alt text tells people what is in an image, such as text or basic essential details. Many people with blindness, low vision, or other visual impairments use screen readers to access websites, applications, and documents. When the screen reader comes across an image, the alt text is read out loud to tell the person what the image is and what it looks like. Search engines also index alt text information and consider it a factor when determining search engine ratings.
While there are some applications that can generate automatic alt text, the most useful and meaningful alt text comes from people taking the time to write a short description (about 140 characters) and adding it to their social media posts.
An image description gives more details than alt text and allows someone to learn more about what is in an image that goes beyond alt text. Alt text gives the user the most important information while image descriptions provide further detail. For example, alt text tells someone that there’s a puddle on the floor, and image description tells someone that the puddle on the floor is in the middle of the floor and it is orange juice. A growing number of users will add both alt text and image descriptions to their posts, often putting the image description in the caption or comment section.
Twitter supports alt text up to 1,000 characters, though alt text cannot be added or edited once an image or gif is posted.
Alt text can be added to tweets that contain multiple images, though each image will need its own alt text.
Instagram supports alt text up to 100 characters, and alt text can be added or edited once a picture is posted.
Facebook supports alt text up to 100 characters, and alt text can be added or edited once a picture is posted.
Tumblr supports alt text up to 200 characters, and alt text cannot be added or edited once a picture or gif is posted.
Pinterest does not technically support alt text, however, if an image is posted on Pinterest, the alt text is by default included in the description of the post. I recommend using image descriptions in the caption of pins to provide more information about images.
LinkedIn supports alt text up to 120 characters, and alt text cannot be added or edited once a picture is posted. Alt text also cannot be added or edited on mobile apps.
By Veronica Lewis/Veronica With Four Eyes, www.veroniiiica.com
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