You can add a description, sometimes called alt-text, to your photos so they’re accessible to even more people, including people who are blind or have low vision. Good descriptions are concise, but present what’s in your photos accurately enough to understand their context. For anyone using a screen reader this will read the Tweet text and the alternative text you provided for your image. The same concept applies to adding images to other social media, blog posts and websites.

On your phone when you add an image you will see a paint brush icon. Click this and it takes you to the ‘Edit photo‘ page. Here you can select the ALT option. This stands for alternative text. You have up to 1000 characters to describe your image. Then tap Done and then Save. This will take you back to your tweet which you can then finalise and send.

From twitter.com, once you add an image you will see ‘Add description‘ underneath it. Click this and add your description. Then click Save. This will take you back to your tweet which you can then finalise and send.

Description tips

You don't necessarily need to say "image of" in your alt text for users to know it's an image. Screen readers will announce that it's an image. But it can help readers to specify if it's a hand-drawn image, Polaroid, infographic, screenshot, chart, map, diagram, or so on.

— Accessibility Awareness (@A11yAwareness) July 28, 2022