Starting now, users can add a description of upto 420 characters to the images they upload on the site using its iOS and Android app. The character description in photos can then be used by the visually impaired, through assistive technologies such as text-to-speech recognition and braille displays (a tactile writing system used by people who are blind or visually impaired, traditionally written with embossed paper).
“Starting today, people using our iOS and Android apps can add descriptions — also known as alternative text (alt text) — to images in Tweets. With this update, we’re empowering everyone to ensure content shared on Twitter is accessible to the widest possible audience.The next time you add an image to a Tweet, each thumbnail in the composer will have an add description button. Tap it to add a description to the image. People who are visually impaired will have access to the description via their assistive technology (e.g., screen readers and braille displays),” Twitter wrote in a blog post.
Users can activate the feature by heading over to Settings and Accessibility. Twitter also adds that even publishers and third-party clients can make use of this feature with REST API and Twitter Cards.