When you use the image uploader, it creates something like this:
[![enter image description here][1]][1]
This text is invisible to most people in the preview and serves no obvious purpose, so many people ignore it. However, it is very important, since it is:
- Used by screen readers
- Used when the image is blocked on the network or broken
Could the "Review your question" button catch this and issue an error or warning? The text of the message should explain what to do, along these lines:
- Replace images of text with plain text
- Replace images of tables with tables
- Describe any remaining images as if the images will be missing from the post
- Link to an explanation for what alt text is used for and more detailed guidance on how to make it useful
On code sites, how to format code is relevant and maybe should be linked. (On sites where code is almost never relevant, I would not want to encourage code formatting.) Quite a few sites close questions with images of code or errors on sight, so this could help with that.
Unlike some other notorious errors/warnings, it should be possible to determine without any false positives or negatives if this is what the alt text is (or the text of a link, as it will be for low-rep users).
There's never a reason to have "enter image description here" as the alt text (except that it makes inaccessible posts easily findable). There is a risk that people will see the message and make an equally inaccessible alt text, something that's harder to keep track of, but I hope this change would be a net positive overall.
(Of course, I would like to see something similar happen on answers, if possible.)
