Comment by michaelbuckbee a day ago
I really like how you framed this as the takeaway or learning that needs to happen as what should be in the alt and not a recitation of the image. Where I've often had issues is more for things like business charts and illustrations and less cute cat photos.
It might be that you’re not perfectly clear on what exactly you’re trying to convey with the image and why it’s there.
What would you put for this? "Graph of All-Transactions House Price Index for the United States 1975-2025"?
Charts would have a link to tabular data. It’s the “business illustrations” that are more about understanding purpose.
Charts are one I've wondered about, do I need to try to describe the trend of the data, or provide several conclusions that a person seeing the chart might draw?
Just saying "It's a chart" doesn't feel like it'd be useful to someone who can't see the chart. But if the other text on the page talks about the chart, then maybe identifying it as the chart is enough?
https://www.w3.org/WAI/tutorials/images/ including how write alt text for charts.
What are you trying to point out with your graph in general? Write that basically. Usually graphs are added for some purpose, and assuming it's not purposefully misleading, verbalizing the purpose usually works well.
It depends on the context. What do you want to say? How much of it is said in the text? Can the content of the image be inferred from the text part? Even in the best scenario though, giving a summary of the image in the alt text / caption could be immensely useful and include the reader in your thought process.
I really didn’t mean to be snarky. Maybe if I was speaking, my tone would have made that more clear, or I could have worded it differently.
“Why is this here? What am I trying to say?” are super important things in design and also so easy to lose track of.
The logic stays the same though the answer is longer and not always easy. Just saying "business chart" is totally useless. You can make a choice on what to focus and say "a chart of the stock for the last five years with constant improvement and a clear increase by 17 percent in 2022" (if it is a simple point that you are trying to make) or you can provide an html table with the datapoints if there is data that the user needs to explore on their own.
Accessible info graphics [1]
[1]: https://web.archive.org/web/20130922065731/http://www.last-c...
but the table exists outside the alt text, right? i don't know a mechanism to say "this html table represents the contents of this image" , in a way that screen readers and other accessibility technologies take advantage of
The figure tag has both image and caption tags that link them. As far as I remember, some content could be marked as screen reader only if you don't want for the table to be visible to the rest of the users.
Additionally, recently I've been a participant in accessibility studies where charts, diagrams and the like have been structured to be easier to explore with a sr. Those needed js to work and some of them looked custom, but they are also an alternative way to layer data.
"A meaningless image of a chart, from which nevertheless emanates a feeling of stonks going up"