CaptionsAlt text, short for alternative text, is a plain description of a picture. A screen reader reads it aloud so a person who cannot see the photo knows what it shows. It also helps search engines understand an image and appears when a picture does not load.
How to write it
- Say what the picture is: a photo, a drawing, a screenshot.
- Name the main thing: "two children flying a kite on a rooftop".
- Add what matters for the post: a place, a colour, a name if the person is known and agrees.
- Stop. Alt text is one or two sentences, not a paragraph.
Good and poor examples
| Picture | Poor | Better |
|---|---|---|
| A thali | food | A steel thali with dal, rice, two rotis, a green salad and a small bowl of curd |
| A group photo | us | Six friends in white shirts standing on a beach at sunset, laughing |
| A screenshot | screenshot | Screenshot of the settings page with the "Privacy" option highlighted |
Where to add it
Most apps have an option called alt text or accessibility text in the advanced settings of a post. If your app has none, write a short description at the end of the caption instead. On your own website it goes in the alt attribute of the image tag.
Do not stuff it
Do not fill alt text with keywords. It makes the post unpleasant for screen reader users and is treated as spam by search engines. Describe the picture, and the search value follows naturally.
Related reading: how to write a caption.
Questions people ask
Do emoji need alt text?
No. Screen readers read emoji by their own names. Just use them in small numbers so the sentence stays readable.