No validation has been attempted yet. Lots of changes left. This
is visibly not (very) different from the previous CSS layout. But
some simplifications have been made.
Might cause issues with local changes to themes and CSS. Also maybe
javascript which depends on certain legacy microformats elements.
The move to microformats2 is motivated by the announcement that all
microformats should be migrated to version 2, as of 2014-06-20 at:
http://microformats.org/2014/06/20/microformats-org-turns-9-upgrade-to-microformats2
The File object now stores width and height of files that can
supply this kind of information. Formats which we can not read
natively in PHP do not currently benefit from this. However an
event hook will be introduced later.
The CreateFileImageThumbnail event is renamed to:
CreateFileImageThumbnailSource to clarify that the hooks should not
generate their own thumbnails but only the source image. Also it now
accepts File objects, not MediaFile objects.
The thumbnail generation is documented in the source code. For
developers, call 'getThumbnail' on a File object and hope for the best.
Default thumbnail sizes have increased to be more appealing.
