Ensure images are accessible #898
Description
I believe currently very few of our images have descriptions which will produce alt text, which is necessary to make our books screen reader accessible. We should make sure every image has a <shortdescription>, and probably most of them would benefit from a <description> as well. See Subsection 4.40.3: Advice for Writing Image Descriptions for a longer explanation.
Note that <shortdescription>s should be limited to 125 characters and must be plain text. A <description> could use things like <m> tags.
It is unclear to me if the handful of Doenet interactives we have are accessible at all, and how that might be remedied.