@jupiter_rowland @fediverse I've wrestled with this over the years. Pictures of text is clear: it must contain all of the text. But in the situations you're describing, I'd say do enough to let the listener know if they want to learn more, then add a link to an alt-text blog post which gives the whole shebang. (I've heard varying reports that longdesc is inconsistently supported, so a separate link immediately below the image is best.)
ChasMusic
joined 2 years ago
@jupiter_rowland @fediverse
tl;dr: Clear and concise alt-text goes in the alt attribute. Full description of absolutely everything in the picture plus explanation if necessary goes on the linked page with the link being placed immediately following the image.
Added: Be sure that link is meaningful, for example, "Alt text for image of the lighthouse control room" and not "Alt text for above image" since blind people will sometimes listen to a list of link text with no other context.