It should work now. Thanks for your interest.

> If you care about alt in markdowns, isn't it simpler to use the <img> tag directly in the markdowns file? Markdowns does support inserting html.

It's more common to use markdown syntax  which is coverted to <img> tag during doc build process. This approach keeps the markdown clean.

Unfortunately it seems sharing this link triggered a anti-spam mechanism on my GH account. Have raised a case with support.