PostEaseThe short answer
Alt text, short for alternative text, is a written description attached to an image. People who use screen readers hear it in place of the picture, so a post’s image carries its meaning to them too. Most people never see it: it sits behind the image rather than under it.
LinkedIn’s Help Center puts the purpose plainly: alt text “allows members using voice-over screen readers to understand what’s in the image.” Pinterest says the same of Pins: it makes a Pin “more accessible to people who rely on screen reader technology and who might not be able to see what’s happening.”
Where each platform keeps it
Every major platform has an alt text field, but each puts it in a different place and treats it differently. From their own documentation:
| Platform | Where you add it | What to know |
|---|---|---|
| Alt. text, below the image after uploading | LinkedIn may add alt text itself when you leave it empty; on desktop it tells you, on mobile it doesn’t | |
| More options, then Alt text, when creating or editing a Pin | Up to 500 characters, on standard and video Pins | |
| Bluesky | On each image before posting | The AT Protocol, which Bluesky is built on, gives every image in a post an alt field, up to 4 images; search also matches words in alt text |
How to write it
Good alt text says what the image is for in this post, in the fewest words that do it:
- Describe what matters to the post: “A bar chart: replies doubled in March” beats “a chart”.
- Leave out “image of” or “picture of”; screen readers already say it is an image.
- Include any words that appear in the image, such as a quote card’s text or a slide’s headline.
- Keep it to a sentence or two for a photo; a chart or infographic needs the numbers it shows.
- Write one for each image in a carousel, not only the first.
- Do not use it for hashtags or keywords; it is read aloud word for word.
Alt text and search
Alt text is written for people, but it is also text a platform can read. Bluesky’s own search guide says phrase searches include “posts that use the phrase in its alt text on images as well,” so an accurate description can help the right people find a post. That is a side effect, not a reason to stuff it: a description written for a listener is also the one that matches what people search for.
Examples
The same images, described weakly and well:
| Image | Weak | Better |
|---|---|---|
| A product photo | Mug | A white ceramic mug with a hand-painted blue wave, on a wooden table |
| A quote card | Quote | Text: “Ship the small version first.” in white on a black background |
| A results chart | Chart showing growth | Line chart of weekly followers, rising from 1,200 in January to 3,400 in June |
| A behind-the-scenes photo | Studio | Two people sanding a chair frame in a workshop full of sawdust |
Alt text in PostEase
In the PostEase composer, each attached image has its own alt text field, and it is sent with the image to X, LinkedIn, Pinterest and Bluesky. The composer checks the length against the shortest platform limit, Pinterest’s 500 characters, before you schedule. The field is for images; PostEase does not send alt text with video, so describe what a video shows in its caption. YouTube, X, LinkedIn (personal profile), Pinterest, Bluesky, and WordPress publishing are live today; Instagram, TikTok, Facebook, and Threads are pending each platform's own API approval.
Questions
Who reads alt text?
People using screen readers hear it in place of the image. LinkedIn and Pinterest both say it is not shown to other viewers.
How long should alt text be?
Long enough to say what the image shows and why it is in the post: usually a sentence or two. Pinterest allows up to 500 characters.
Does LinkedIn add alt text automatically?
It may, for images without it. LinkedIn says you are alerted on desktop but not when uploading from a mobile device.
Does alt text help a post get found?
On Bluesky, phrase searches include words in alt text. Write it for people first; an accurate description is also what matches searches.
Sources
- LinkedIn, Add alternative text to images for accessibility, checked October 2026.
- Pinterest, Add alternative text to your Pins, checked October 2026.
- AT Protocol, app.bsky.embed.images lexicon, checked October 2026.
- Bluesky, Tips and tricks for Bluesky search, May 2024.