Alt tags on tweet images

I learned this morning via a comment that Twitter supports alt text descriptions for images. I didn’t think that it did, and said that it didn’t, but someone kindly corrected me.

When I post equations as images on this site, I always include the LaTeX source code in an alt tag. That way someone using a screen reader can determine the content of the equation. It also helps me if I need to go back and change an equation. I’d like to do the same on Twitter.

Unfortunately, it seems support for this feature is inconsistent. Maybe it’s new. The software I use to manage my Twitter accounts apparently doesn’t offer a way to add alt text.

When I use Twitter via its web site, I am able to write alt text but not able to read it. Maybe you have to have accessibility features turned on, which would be unfortunate. People who do not use screen readers occasionally benefit from being able to read photo descriptions. I could imagine, for example, that someone might be curious to see the LaTeX code I used to create an equation image.

I tried a couple experiments, one on my personal account and one on my AlgebraFact account. On the latter, I posted an image of the quadratic formula with the text description

    x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

When I look at the tweet while logged into my AlgebraFact account, I see a little black box in the lower left corner of the image with “ALT” in white letters.

quadratic formula with ALT box in lower left

I do not see the same box on an image I posted from my personal account. When I log into my personal account, I no longer see the ALT box on the AlgebraFact tweet but I see one on an image I posted.

Question and request

It appears that with default settings, users cannot see image descriptions. What do you have to do to see the descriptions?

I intend to always put LaTeX source in the alt tag of equation images on this site. If you run across an equation without alt text, please let me know.

3 thoughts on “Alt tags on tweet images

  1. If reading of that text will be easy possible, than it will be the method for breaking “length of Twitter note” rule… No one reports such feature, till now…

    I suppose that that feature is used only by Twitter designers itself for learning some picture classify and sorting AIs. Probably for content filtering and other commercial purposes

  2. Twitter alt text has a few limitations. You only see the ALT badge on your own tweets if they have alt text, but, like you discovered, you don’t see the badge on tweets by others and you can’t easily see the alt text for any tweets, even your own.

    There are a few browser extensions that make it easier to view the alt text and harder to send tweets with images without them. I like https://www.abitofaccess.com/alt-or-not — out of the box it makes all alt text visible for all tweets. It can also be configured to disable the Tweet button in the tweet composer until you’ve added alt text. Both features have really helped me improve my use of alt text in my tweets.

  3. I know this doesn’t exactly fix the problem, but many accessibility-forward accounts I follow tend to tag @ImageAltText in the replies to images posted on Twitter. The account is a bot which will tweet out the contents of the alt text. Might be worth doing, and I’m sure the software you use for tweets can code in a command to tag the bot when an image is used. Hope this helps!

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