@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.)