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As a follow-up question of Stop image upload completion from stealing cursor focus, I wonder what percentage of images on SE have a meaningful alt-text.

Edit: by meaningful, I mean useful.

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  • uhh... there are tons of images in SE and I'm not really sure if SE is maintaining stats about 'meaningful' alt-text. Jan 29 at 10:17
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    @RandomPerson - as a rough statistic, someone can run a data.SE query, counting images that have "enter image description here" or blank alt text versus other text. For instance, I use this query to find posts and add alt text.
    – Mithical
    Jan 29 at 10:24
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    ‘Not meaningful’ and ‘default text’ are not the same. Determining if it is ‘meaningful’ is hard to impossible.
    – Jon Custer
    Jan 29 at 17:57
  • We need an AI trained in semantics - both general and abstract to scan for meaningfulness.
    – W.O.
    Jan 29 at 18:28
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    @JonCuster I posit that the exceptionally vast majority of "not meaningful" text is the default text. Because I've hardly seen anybody change it. Those who do (and don't simply delete it) tend to write something useful.
    – VLAZ
    Jan 29 at 20:12
  • @VLAZ that was my thought as well, but here on Meta.SE the default text is only used slightly more than a third of the instances. Blank texts are also common, but at least half of the images has some kind of custom alt text. Whether those are really meaningful, that's another question ...
    – Glorfindel Mod
    Jan 29 at 20:19

2 Answers 2

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Here is a SEDE query which analyses the alt text of the all images included as Markdown in every post. No doubt it's possible to extend this to images included as HTML (<img alt="...), but those are relatively rare. Anyway, it gives a general idea of which alt texts are used and how often. They are sorted by frequency, and I expect the most meaningful to be rather unique, so at the bottom of the list.

There are 61k of those images on Meta Stack Exchange, so about a third has the boilerplate 'enter image description here' (a lot less than I expected). 'alt text' was the default in early years, as @Sonic noted. No alt text (the blank entry) is also quite common (12% of the occurrences) - probably mostly from users manually entering the Markdown with an already uploaded or hotlinked image. The usernames seem to be coming from automated Town Hall transcripts.

There are about 23k unique alt texts on Meta Stack Exchange. When you run the query on other sites, please be aware that SEDE can only return 50k rows - the total # of images will be correct though. Anyway, it'll definitely time out on Stack Overflow - feel free to fork it to include a date range or something, or run it with access mere mortals daren't dream about.

top results of SEDE query mentioned above

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    Interesting. Why are so many of them usernames? Also, a whole lot of them appear to be links; that might be an error in the query?
    – Mithical
    Jan 29 at 18:13
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    "alt text" was the original default used in SE's early years. Also, the capitalized version in fifth place is due to a prolific editor across the network who uses an automated editing tool that capitalizes it when they make other changes. Jan 29 at 18:23
  • @SonictheAnonymousHedgehog that was my guess for the capitalization as well, but I didn't have time to confirm it :)
    – Glorfindel Mod
    Jan 29 at 19:38
  • Note that no alt text isn't necessarily an accessibility problem, since the content of the image may be described sufficiently in the surrounding text (and decorative images don't need alt text). It would be a problem if those images are links, however, since it means there's no good description for where the link leads.
    – Laurel
    Jan 29 at 22:58
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I took a slightly modified version of Glorfindel's query and ran it where you can't: against Stack Overflow. It took a long time, as you can imagine, and yielded that people are generally much better about this here on meta than on Stack Overflow - perhaps because the audience here is of generally more experience on the network, or that more accessibility issues are discussed (and so set better examples), or because Stack Overflow's image population is largely weighted toward newer users asking questions to solve immediate problems and not as interested as answerers in providing information for future readers.

Here is a partial result; I stopped after we got to single-instance:

Total images and breakdown of alt text

I casually scanned through the first, oh, thousand or so entries, and found very few that seemed like meaningful text.

And especially because "meaningful" is itself subjective, and the tail is really, really long, I think it will be very hard to come up with any useful number or percentage.

I don't know what we can now do with that information, especially at scale, other than make a subjective determination that it is bad enough we need to implement some kind of feature to force users to add descriptive text.

I think like the "explaining down-votes" debate, you could argue that lazy people who want to watch the world burn will work around the system by entering garbage, adding or removing a single character, putting in a poop emoji, and what have you.

As mentioned in a comment, it is still hard to draw a line indicating accessibility problems, because lack of alt text on its own doesn't indicate (and would be impossible to determine programmatically, again at scale) whether there is helpful context above/below the image, that simply doesn't happen to be repeated in the alt tag. While it can't hurt to repeat it there, it could be an accessibility issue in the opposite way (since the same information might be repeated), and may make the work of maintainers harder, since future edits will need to keep the alt text in sync in two places.

Honestly I think positive reinforcement is the best policy here, and will admit that I am already much more aware of my lack of attention to detail in this area. Places where changes won't jeopardize site functionality, like the staging ground, post wizards, the tour, and FAQs, as well as our own behaviors when helping other users, can emphasize the usefulness of including this information.

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    cough cough
    – Mithical
    Jan 30 at 20:21
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    @Mithical I've seen that, I just don't think having the software nag you to include something other than the boilerplate will do much except push people to change the boilerplate in the easiest possible way to get around the nag. (That doesn't mean I disagree with the feature request, I'm just skeptical it will have much impact on my query results.)
    – Aaron Bertrand Staff
    Jan 30 at 20:39
  • There are browser extensions that will let you toggle images off and on. It quickly becomes very clear which alt text is helpful and which isn't ;) Maybe for the next Global Accessibility Awareness Day it would be fun to let people opt-in to experience parts of Stack Exchange with no images or with a screen reader or with simulated color-blindness. It can really change your perspective.
    – ColleenV
    Jan 30 at 20:44
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    @ColleenV Thanks, I will bring exactly that suggestion for our next Community-a-Thon as well.
    – Aaron Bertrand Staff
    Jan 30 at 20:45
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    @ColleenV Nothing proprietary or confidential here, and certainly no promises, but an answer I just posted on our internal Q & A about feedback for the event.
    – Aaron Bertrand Staff
    Jan 30 at 21:03
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    Awesome. I don't remember exactly when the light bulb lit up about accessibility for me, but using a screen reader to navigate a web site is an eye opening experience. (pardon the terrible wordplay) Turning off images is a really easy place to start though. For chromium-based browsers I like this very simple extension: chrome.google.com/webstore/detail/images-onoff/…
    – ColleenV
    Jan 30 at 21:43

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