Last modified: 2013-07-04 10:34:17 UTC
[Not urgent.] Frameless images are special; the caption is meant to be the alt text, unless alt= is also set, in which case it's ignored - but Parsoid outputs a <figcaption> for images regardless of type (thumb, framed or frameless) - and doesn't output the alt at all, which is bug 45208. There's a hack in VisualEditor to ignore <figcaption>s for these as part of bug 50113, but Parsoid should fix these in due course.
This is by design. See http://www.mediawiki.org/wiki/Parsoid/MediaWiki_DOM_spec#Images for documentation and rationales.
[Parsoid component reorg by merging JS/General and General. See bug 50685 for more information. Filter bugmail on this comment. parsoidreorg20130704]