Writing a description for an image is a no-brainer when you are limited by Twitter’s character count or if you simply want to explain the context, but adding it has been a bit tricky so far. That changes now, as Twitter now lets you directly add a text-based description when you select an image without going to the image edit settings.
Starting today, you’ll see an alt-text field on Twitter’s mobile app and desktop client that will let you quickly add an appropriate description for an image in your tweet. Twitter says this is an accessibility feature that will “enable folks who use screen readers to interpret images in Tweets.”
On mobile, a black text field below the image appears with the “Add description…” caption. You can tap on it and fill it with the description you have on your mind. As for the desktop client, you just add an image and tap on it to find the “ALT’ section at the top for adding the description. The change is live for regular tweets as well as direct messages you send to a friend or follower.