Twitter ( TWTR ) said people using Apple ‘s ( AAPL ) iOS or Alphabet ‘s ( GOOGL ) Google Android can now add descriptions to images in tweets, a benefit to the visually impaired. The update allowing descriptions — also known as alternative text — empowers “ everyone to ensure content shared on Twitter is accessible to the widest possible audience,” said Twitter engineer Todd Kloots in a blog post Tuesday. . “Photos have been at the center of some of the biggest moments on Twitter,” said Kloots. “ As a core part of the Twitter experience, it’s important that images shared on our platform are accessible to everyone, including those who are visually impaired.” People can use the feature via the “compose image descriptions” option in the Twitter app’s accessibility setting. When an image is added to a tweet, the user can tap the “add description” button and insert a description of up to 420 characters to the image. Visually impaired people will have access to the description by using assistive technology, such as screen readers and braille displays, Twitter said. Smartphones have other accessibility features, including VoiceOver, the iPhone’s built-in gesture-based app that reads text on a touchscreen aloud, and Google Android’s TalkBack, through which visually impaired users can access anything on their phones. Voice Activation Usage Still Low Voice-activated services, including Apple’s Siri, Amazon.com ‘s ( AMZN ) Alexa, Alphabet’s Google Now, Microsoft ‘s ( MSFT ) Cortana and others, can assist all consumers, including the visually disabled, as people increasingly rely on mobile phones for shopping, communicating and information. But surveys have found those voice-activated services aren’t getting much use. Just 13% of U.S. mobile phone owners use a voice-controlled personal assistant on their device each day, according to a survey last June from 451 Research. The Americans with Disabilities Act requires websites and mobile applications to be accessible. Google announced its Google Impact Challenge: Disabilities last year with a $20 million grant for technology innovators in the nonprofit community who work on technology to make people with disabilities more independent. In addition to Twitter and Microsoft, Adobe Systems ( ADBE ), Dropbox, LinkedIn ( LNKD ), Yahoo ( YHOO ), Facebook ( FB ), Intuit ( INTU ) and others have jointly asked universities to train computer students in accessibility software design and are requiring new hires to demonstrate some familiarity with it, according to the Mercury News. Besides facing competition from rivals such as Facebook, Twitter is struggling to expand its user base as its user growth has slowed. Twitter has launched programs to reel in “logged out” users who visit Twitter’s site but don’t have accounts of their own, making them less coveted by advertisers. Twitter stock was up 2% in afternoon trading in the stock market today , near 16. Image provided by Shutterstock .