Pandoc epub to pdf - remove captions

Question

I'm looking for a way to remove auto generated captions when turning epub book into pdf (the epub has those hardcoded, so I get double captions under images).

I've tried cobbling together a lua filter, but as I basically know nothing about lua nor writing pandoc filters not surprisingly it failed.

Any ideas howto approach it?

function Image(img)
    local new_caption = pandoc.Str' '
    local new_title = pandoc.Str' '
    local new_attr = pandoc.Str' '
    return pandoc.Image(new_caption, img.src, img.title, img.attr)
end