Captions should be enabled by default for images within the posts section.

[bershatsky]

I should be able to use markdown like this (ala iA writer) to generate a caption below an image.

My ![alt attribute goes here!](/path/to/train.jpg "This is a Title" )

Is there any way to make this work?

[kdkasad]

Use Hugo's figure short code instead. It's supported by PaperMod whereas standard markdown images aren't (AFAIK).