Twitter's making it easier for users to add text descriptions to their uploaded images, with a dedicated '+ALT' button displayed on the image itself.
As explained by Twitter:
"Adding descriptions to images is a great way to include everyone in your conversation. These descriptions, aka alt-text, enable folks who use screen readers to interpret images in Tweets. Starting today, you no longer need a setting to add alt text."
Twitter added the capacity to include alt-text descriptions with uploaded images back in 2016, but the process has thus far involved tapping or clicking through to an extra menu prompt, which not all users are aware of. Now, as you can see in the example above, there'll be a new '+ALT' indicator on the image, which will make it easier to tap through and quickly add in text detail.
As noted by users, the added visibility for the option will mean that people who hadn't considered alt-text before will now be more aware of the option, which will likely mean that more take the time to do so. And that can have major benefits for visually impaired users. Around 7.6 million people in the US suffer from visual disability, in some form, and providing basic descriptors within your uploaded visuals can have a major impact on their online usage experience.
In addition to this, it can also make your images more searchable. Twitter doesn't enable visual search through alt-text at this stage, but the included information can still be accessed and used to categorize your content.
Basically, if you can add in an image description, you should do so, and now that it's front and center, hopefully more people will.