How to Add Alt Text on Bluesky (and How Few Posts Have It)
To add alt text on Bluesky, attach an image in the composer, tap the small ALT button in the corner of the image, type a description and tap Save. The button switches from a plus sign to a checkmark when the image has alt text. You can't add it after you post. To make sure you never forget, turn on Settings > Accessibility > Require alt text before posting, and the app won't post an image without it.
Alt text is a short written description of an image that screen readers read aloud for blind and low-vision people. Bluesky also shows it to anyone who taps the image. The steps are quick, but most people skip them. I replayed half an hour of Bluesky's public post stream on October 26, 2026 and found that 74% of the 14,965 image posts had no alt text at all. Accounts with 10,000 followers did no better than accounts with 100.
(Disclosure: I make Agent Sky, a Bluesky growth tool. More on it at the end.)
How Do You Add Alt Text on Bluesky?
Tap the ALT button on the image before you post. It works the same in the iPhone app, the Android app and bsky.app. I checked these steps against the code of Bluesky's official app (bluesky-social/social-app, October 26, 2026).
For an image:
- Start a post and attach your image. The current app takes up to 10.
- Tap ALT in the corner of the image preview. It's top-left, or bottom-left on a phone when you've attached three or more. It shows a + while the image has no alt text.
- Type the description in the Add alt text box.
- Tap Save. The button now shows a checkmark.
- Repeat for each image, then post.
While any image is missing alt text, the composer shows a note under the images: "Alt text describes images for blind and low-vision users, and helps give context to everyone."
For a video: after the video is attached, tap Alt text under it. On bsky.app the button is called Captions & alt text, and the same box lets you add captions as a .vtt file. Video alt text is easy to miss, so if the video needs explaining, say it in the post text too.
For a GIF: pick a GIF from the built-in GIF search, then tap its ALT button. Bluesky fills the box with the description the GIF provider supplied. Check it before you post, because that text describes the GIF, not why you posted it.
Is there an AI alt text generator? Not in Bluesky's app. Some third-party browser extensions will draft alt text with AI. If you use one, read what it wrote before you post.
Can You Add Alt Text After Posting on Bluesky?
No. Alt text is part of the post, and Bluesky posts can't be edited. The only fix is to delete the post and post it again with the alt text. You lose the likes and reposts it already had.
The setting that prevents this is easy to miss:
| Setting (Settings > Accessibility) | What it does |
|---|---|
| Require alt text before posting | Blocks the Post button and shows "One or more images is missing alt text" (or videos, or GIFs) until every one has a description |
| Display larger alt text badges | Makes the ALT labels on images, videos and GIFs bigger, so it's easier to see which posts have alt text |
Both are off by default, and both are saved on your device. So if you use Bluesky on your phone and on bsky.app, turn them on in each. To turn the reminder off, switch the same toggle off. My data below shows people describe every image or none, so a reminder at posting time is what helps.
How Many Bluesky Posts Have Alt Text?
About one image post in four. Here's what 30 minutes of Bluesky looked like (14:31–15:01 UTC, Monday, October 26, 2026, 91,451 new posts):
| What I measured | Result |
|---|---|
| Image posts with alt text on every image | 25.6% (3,831 of 14,965) |
| Image posts with no alt text at all | 74.3% (11,117) |
| Image posts with alt text on some images but not others | 0.1% (17) |
| Posts with 5–10 images that had alt text on every image | 5.2% (12 of 229) |
| Video posts with alt text | 12.1% (217 of 1,796) |
| Replies with images that had alt text | 20.9% (vs 26.4% for top-level posts) |
| Image posts from accounts that mark themselves as bots | 73.7% had alt text (483 posts) |
The 25.6% figure flatters people. Automated accounts (news feeds, weather and quake alerts, art bots) often fill in alt text from a template, and they push the number up. Posts that carry a language tag, which the official app adds for you, had alt text 21.8% of the time. Posts with no language tag, mostly from tools and bots, had it 44.0% of the time.
Bigger accounts don't do it more. I looked up the follower count of every account that posted an image. This table uses only the language-tagged posts, to keep the bots out (9,095 accounts):
| Account size | Accounts | Image posts with alt text |
|---|---|---|
| Under 100 followers | 2,576 | 19.7% |
| 100–999 | 3,640 | 21.8% |
| 1,000–9,999 | 2,357 | 24.4% |
| 10,000–99,999 | 497 | 20.7% |
| 100,000+ | 25 | 22.2% (only 36 posts) |
Language matters more than size. English image posts had alt text 27.0% of the time and German ones 36.0%, but Spanish posts were at 10.9%, Japanese at 6.0% and Korean at 1.0%.
What I take from it:
- People describe every image or none. Only 17 of 14,965 posts described some images and skipped others. That's why the Require setting works.
- More images, less alt text. Posts with 5 to 10 images (possible since the app raised the limit from 4) had full alt text only 5.2% of the time.
- When people write it, they mostly write it properly. The median description, across 4,716 of them, was 71 characters. Only 1.5% were filler like "image" or "photo 1", and 0.7% were file names. 6.4% were 10 characters or shorter.
- Some alt text is the post copied again. 5.0% of descriptions were exactly the post's text. That tells a screen reader user nothing new.
- 4.5% of descriptions had a hashtag in them. Hashtags in alt text don't become tags, so they're just noise for screen readers.
How Do You See Alt Text on Bluesky?
Look for the small ALT label in the corner of an image. If it's there, tap the image to open it full screen, and the alt text appears at the bottom. Long text is cut to three lines. Tap it to read all of it. On videos and GIFs, tap the ALT badge itself to open the text. No ALT label means the poster didn't add any.
Alt text is also searchable. When I tested Bluesky's search, a quoted phrase search matched words inside image descriptions, not just post text. So a good description can help your post show up for the words people search for.
How Do You Write Good Alt Text?
Describe what someone would miss if they couldn't see the image, in a sentence or two. A few rules that cover most posts:
- Lead with what matters. "Graph: Bluesky signups doubled in November" beats "A line graph with a blue line".
- Type out any text in the image. Screenshots of posts, memes and charts are mostly text. If it's long, that's what the 2,000 characters are for.
- Skip "image of" and "picture of". Screen readers already say it's an image.
- Don't repeat the post. Say what the image adds.
- Leave out hashtags and links. They don't work there.
Bluesky's app limits alt text to 2,000 characters. For images it cuts anything longer when you save. For videos it shows a warning. That's a choice by the app, not the protocol, which sets no limit (more in Bluesky's character limits). In my sample, 4.0% of descriptions were over 500 characters, and 4 were over 2,000, so they came from other tools.
Will alt text get you more likes? When I measured that for how to get more likes on Bluesky, I found no measurable effect. Add it because people who can't see your image follow you too.
How I measured it, and the limits. I replayed Jetstream, Bluesky's public stream of network events, for 14:31–15:01 UTC on Monday, October 26, 2026. That gave 91,451 new posts, including 14,965 with images (20,208 images, 4,716 of them with alt text) and 1,796 with video. Image posts include quote posts with images and the newer multi-image gallery posts. GIFs from the GIF picker are posted as link embeds, so they're not in these numbers. I then looked up each image poster's follower count with Bluesky's public getProfiles API (10,641 of 10,714 accounts returned a profile). "Filler" means a description that was only a word like image, photo, picture, screenshot or alt, sometimes with a number. The bot figure uses the label accounts set on themselves. Half an hour on a weekday is one snapshot, and an earlier, smaller sample in our likes post found a lower rate (17.1%). All of it is public data.
Alt text helps the followers you have. I built Agent Sky to find more. It finds active accounts in your niche, follows them at a human pace, well inside Bluesky's limits, and checks for a live follow-back before it unfollows anyone. $9 a month, free to start. To see which of your posts land, try our free Bluesky analytics tool.
Quick FAQ
How do you add alt text on Bluesky? Attach an image in the post composer, then tap the small ALT button in the corner of the image. Type a description in the Add alt text box and tap Save. The button changes from a plus sign to a checkmark. For a video, tap Alt text under it (Captions & alt text on bsky.app).
Can I add alt text after posting on Bluesky? No. Bluesky posts can't be edited, and the alt text is part of the post. To add or fix it, delete the post and post it again with the alt text. To avoid this, turn on Settings > Accessibility > Require alt text before posting.
How do you see alt text on Bluesky? Images with alt text have a small ALT label in the corner. Tap the image to open it full screen and the alt text shows at the bottom. Tap the text to expand it if it's long. On videos and GIFs, tap the ALT badge itself. Settings > Accessibility > Display larger alt text badges makes the label easier to see.
What is the Bluesky alt text character limit? 2,000 characters in the official Bluesky app. For images, the app cuts the text to 2,000 when you save. For videos, it shows a warning. Most people write far less: across 4,716 image descriptions in my sample, the median was 71 characters.