Alt text 101 for Bluesky
Hi! You may be here because I or someone else sent you this link in response to a conversation about alt text on Bluesky. Welcome! Here's some basic info about alt text, its importance, and how to write it for social media!
What is alt text?
Alt text is text that describes an image for people who can't see it. This text is not visible by default when you're viewing Bluesky in your web browser or on your phone; you can see it by tapping/clicking "ALT" on the image. Alt text is usually entered manually by the person who's posting the image. In some cases alt text may be autogenerated by software — usually very badly.
Why is alt text important?
Alt text is very important to people with visual impairments and other types of disabilities. Some of these people use screen reader software, aka text-to-speech software, that reads text out loud to them. Since these people can't see the image, the presence of alt text helps them understand what the picture is and what its context is in relation to the content of the post.
Other people with low vision may be able to see images but may have difficulty making out certain details. In this case, they can read or hear the alt text to get the context of the image.
Alt text is also useful and important to people with certain cognitive disabilities.
It's important that we include alt text for all images on social media. Alt text allows people with various disabilities to enjoy social media in a way that's equitable to the experience of people without disabilities; it allows them to not be excluded from this experience. Alt text, and accessibility in general, are our ethical responsibilities to people with disabilities. We should not consider alt text to be optional. We should regard alt text as required, and always include it if we are able to do so.*
How should alt text be written?
A great rule of thumb is: write alt text like you're describing the image to someone over the phone. What details are important for the other person to know about the image?
The main thing to consider is: what meaning or feeling is the image supposed to convey to the viewer? What does a person reading my post need to know about this image in order for the post to make sense?
Some guides for writing alt text will tell you to describe everything in the image. I think this is overkill in many cases. Things like the color of clothing are not relevant a lot of the time. I think if we insist that people write really detailed alt text, they'll be more likely to just skip it all together, which defeats the purpose. Simple and brief are fine, as long as you cover the most important, most meaningful things. If you want to write a lot of detail, just make sure to start with the most important things; that way a screen reader user can skip ahead if you start to get into less-relevant, less-interesting details.
If your image contains text, you should include all relevant text in the alt text. If you happen to be posting from an iOS device, you can use the Live Text icon to copy and paste the content of the graphical text into your alt text.
How/where do I add alt text?
When you select a pic to post on Bluesky, it'll show you the pic with a little button that says "+ Alt"; you can tap/click that and add your alt text there.
For video, the link to add alt text will appear under the video when you've selected it; you might have to scroll down a bit.
Alt text and gifs
Most or all of the gifs that are available on Bluesky come with autogenerated alt text. In almost all cases, the autogenerated text is very bad! It's usually just a physical description of things, it's often wrong (which means it's probably generated by garbage AI), and it usually doesn't give any context of what the gif is about. Make sure to delete all that junk and write something that's actually useful! Leaving the bad alt text in there is arguably worse than including none at all.
I wrote some more about this topic: Bluesky, gifs, and autogenerated alt text.
Set alt text to be required in Bluesky
Bluesky has a setting that will remind you to include text when you're posting an image. Go to Settings / Accessibility, and check the box next to "Require alt text before posting." As of this writing (December 2024) you have to set this separately in both the mobile app and the desktop website.
Alt text and search
On top of our ethical responsibility to people with disabilities, alt text is also great for search. When you post an image with alt text on Bluesky, your post will appear in searches for the terms that you entered. You can easily search your own posts on Bluesky this way; just search "from:me term" — without quotes, and replace "term" with the word(s) you want to find. (Fyi, alt text for gifs and videos currently doesn't figure into search for some reason; just regular images for now.)
*If we are able to do so
Some people have physical and/or mental challenges that make alt text harder or impossible for them. This is perfectly understandable. Now, when I say, "if you are able," what I don't mean is: if you're not in too much of a hurry; if it's not too much trouble. Those of us who are able to include alt text have a responsibility to do so. Even if it's just a reply to a friend. Even if it's a dumb, nonsensical post. Even if you have a small audience. Our posts appear in other people's feeds whether that's our intention or not. It's our responsibility to always post accessibile content so that all types of people can engage with it.
Speaking of the content we're putting into other people's feeds, I also wrote an article about Bluesky, accessibility, and reposting.
That's the basics! There's really no need to overthink alt text! Just make sure to include it every time if you can.
– Manning
Questions/comments? Feel free to contact me at manning@manningkrull.com. I update these articles pretty frequently — best practices evolve over time as the world of digital quickly changes, and I always welcome insights from others.