Convention to support alt text in notebooks

[ryanlovett]

I’ve tried using jupyter-book and quarto to produce html/book output from a series of notebooks and was wondering how to add alt text for output cells with figures. nbconvert supports generating alt tags when alt is in the cell metadata. Should other apps adopt the same approach? Does there need to be more formal guidelines around this?

I was thinking of filing issues with jupyter-book/sphinx and quarto to ask that they support the same, but I don’t know if this one method should be adopted by all.

Link to discourse thread: https://discourse.jupyter.org/t/convention-to-support-alt-text/14936

[ryanlovett]

Re: (from @trallard on discourse)

IMHO - the best approach would be to have the alt-text within the cell metadata and would align nicely with what nbconvert does already in case anyone is using both (nbconvert + jupyter book).

Some followup questions:

Since this would be a convention and not part of the notebook format itself, how would notebook-consuming tools like jupyter-book and quarto know that they could/should do something with it? Where could it be documented?

If it was put in the metadata.jupyter namespace, does that help the community become more aware of it? Could it be documented in the "Output metadata" section of the "Notebook file format" doc?

[isabela-pf]

For some history, here's a related issue at #37. It was closed by a change at the IPython level.