If it's a screenshot of text, write out the text as the alt-text. Mastodon has a feature where you can choose to 'detect text from picture' from the image after attaching it. You do often have to clean up the generated text, and it struggles especially with symbols. See attached, and also read the alt-text to see how I've described this attached image.
You have 1500 characters to play with (on default Mastodon, at least), but you don't have to use all of them. If you're low on spoons or aren't sure what to write, just adding 'a photo of a dog' or 'a painting of some trees' is better than nothing.
Once you start getting used to writing descriptive alt text that covers the core elements of the image and conveys the important bits, you can start expanding on that -
For example, 'A colour photo of a dog from the neck up. It's a grey-black short hair dog with white patches that frame its eyes and nose. Its head is cocked slightly and its ears are sticking straight up, and it's looking towards the photographer with an eager expression.'
Cover the most important things first, then you can play with more detail (but don't go wild; remember, people using screen readers have to listen to what you've written).
Alt text for traditional art can feel more daunting, especially for abstract work. It's fine to describe your abstract piece as 'an abstract work of art', and if you piece is meant to symbolise or convey a particular concept you had in mind when creating it, feel free to say that. For example,
'An abstract artwork in black and red ink on white paper, with lines that vary in thickness scrawled in a tangled mess. It's meant to represent how my thoughts feel when I have brain fog.'
A lot of people on the fediverse won't boost toots with attached media that doesn't have alt-text, because it's not fair to the blind folk in our community and excludes them from the 'social' part of social media. So if you're here to build an audience around your work, it makes sense to make the extra effort to get into the habit of including alt text with your images; you'll get more interaction with your posts that way.
and don't have the spoons or are otherwise incapable of writing alt-text, there are options! (Also, please, for the rest of us, don't yell at people about not including alt-text. Be nice, be gentle, be informative.)
You can use the :helpdescribe: emoji in your post to ask for others to help you write alt-text, you can use the #Alt4Me hashtag which people keep an eye on to provide alt-text help, or tag the @ imagecaptionspls@a.gup.pe group, and someone will help you out.
Ooh, one last thing: tips on encouraging use of alt-text!
If you find a toot you'd really like to boost, but it doesn't have alt-text;
Ask the person if they'd be willing to add alt text so that you can boost their post. Be nice.
Write the alt-text yourself in a reply to their post, with something like 'adding alt-text here before I boost', then boost it - people often look at replies to see if someone else has added alt-text, and often the OP will add it to their image.
@Curator one side note, for selfies ask first because for me personally it really creeps me out hard (dysphoria and all) to describe or read a description of myself. I'm sure I'm not alone with that feeling. I know it's irrational and hinders people who need them, but I also have to satisfy my animal brain to feel safe here :blobcatlove:
mastodon.art is a safe space instance that focuses on providing a safe environment for the most marginalised people in our community. This includes disabled people, which includes visual disabilities, so it's especially relevant to the culture of our instance that we foster an inclusive, accessible, community.
@Curator
"* Ask the person if they'd be willing to add alt text so that you can boost their post. Be nice."
Those last two words are important. A lot of "requests" I receive for alt text read a LOT like cyberbullying and I have to stop myself from blocking the person making the "request."
@Curator For automatic reminders when you omit alt-text, bots like @PleaseCaption exist. Coded to auto-reply if you forget, and giving you a chance to remedy right away, before humans notice.
Community members who rely on alt text include Blind folk, people with impairments from color blindness or some arthritises or migraines restricting details, people on data-limited internet connections who have to put in extra work to view each image/video, and a variety of Sighted people who need additional context with media uploads.
Text as simple as "Selfie from the waist up."
or "Sunset at the bridge."
or even "singing to music"
can help confirm what the file is.
@SuperTaliaDX I kinda drill down in the same way; instruments, genre, tempo, mood; like it could be 'an ambient electronic track with soft swooshing synths and occasional echoey bass rhythms, that starts slowly and builds in intensity towards the middle, before fading out again'
@Curator as I was doing my best to describe a pose of a model in a photo I posted, I realized that alt-tagging the photo made me study the pose better. I had to be specific about the placement of hands, arms, etc, which will make me more specific about them during the next shoot. Win-win
@Curator As someone who posts paintings, I enjoy the exercise of writing a short description of what I painted, and want to encourage everyone to try it out!
Something here clicked for me: while I almost always add alt text, sometimes I am doing things like live-posting fast moving events like protests and really don't have time or energy to do it. That means I often simply omit photos. What occurred to me is that in those situations in the future, I can probably put out a call for alt text help and (probably?) get a little tag team to immediately post a description in the first comment. I can then later go back and add it to the image easily when things slow down.
@Curator don't forget that alt text can help those of us with colour vision defiency (aka #colourblindness) as we can sometimes not see text on images etc. clearly.
provide extra context and information perhaps not covered in the main body of your toot, making your toot more engaging
That ist exactly not the way that alt texts shoud be used. Alt texts has a specific purpose that is to describe in words, what is to be seen on the image visualy. Not less, not more!
Its not the place for any Kind of "extra information" (no copyright mentions or the like)
@wolf I don't mean things like copyright mentions. I mean providing extra detail that is specific to the image and important to the image being shared. For example, I might post a photo of some birds, and my toot might just say 'some birds in our garden', but in the alt text I'll list the species and describe the birds in more detail.
@wolf I've had loads of converstions with users of screen-readers here on fedi about what kind of alt-text they prefer. Opinions vary, obviously, because different people like different things, but pretty much everyone I've spoken with prefers interesting and informative alt text, even if it's not particularly concise.
@Curator@wolf And what about the rule of "no more than 80 characters" because more could oblige screen-reader users to multiple manipulations ?
True question about users on Mastodon !