Twitter recently announced the addition of ‘alt text’ image descriptions to its official Android and iOS apps, allowing users to add a plain text description to the images they tweet as an accessibility feature.
Image Descriptions can be switched on under Accessibility in users’ account settings in the newest versions of the app on compatible smartphones and tablets – you may need to update the app in order to see the option, and some users are still reporting that they can’t see the setting yet, so it may still not be fully rolled out.
Web Twitter users and those who use third-party ‘dashboard’ applications to manage their social media will have to wait too, as the feature is currently available only via the iOS and Android app.
For those with access to the feature, Image Descriptions adds a new option once you include an image in your tweet, with a button to then add a plain text description which Twitter will use as the image ‘alt text’.
If you don’t know what alt text is, it’s a text description of the image content, which will not be visible directly on Twitter, but is read aloud by screen-reader software used by the visually impaired, meaning they will be better able to understand the context of your tweet.
The text can be up to 420 characters long, three times the length of a normal tweet, and you compose and edit it in the usual way, and cannot edit it after publication of the tweet.
While it is not shown on Twitter, this image description text is already being included in Google Search results – if you search for a phrase that is in the alt text, but not in the tweet itself, the tweet will still show up in the SERPs with the alt text used as its ‘snippet’ or summary in the search results.
As such, you may want to keep your SEO keywords in mind when composing tweets with image descriptions, as this alt text means you now have 560 characters at your disposal – 140 in the tweet itself, and 420 in the description.