When you change the alternate text for an image in a Pressbook via the media library, the text will not update in places where that image is already embedded. This can be confusing if you are attempting to update the alt text within the media library, and already have embedded the image in your Pressbook.

However, setting the alt text for an image within the media library will change the alt text for future instances where the image is embedded.

Affects

This issue affects anyone who is authoring content in Pressbooks with images, and it can impact readers who rely on alt text in Pressbooks. 

Status

This issue is present as of 6/17/2025. There is an open feature request regarding this issue on the Pressbooks Ideas Github Repository, but there is no current release date for a fix. 

Workaround

There is no way to update the alt text for multiple instances of the same image at the same time. To update the alt text for an already embedded image, the author would need to change it in each individual instance of that image embedded in the chapter edit page.

Therefore, if you would like to use the alt text that you specified in the media library, delete and reembed the image. The alt text for an image in the media library will be applied to any future instances where you embed the image.