These two classes in particular seem like they could be improved.

Some other classes found in the structure are mw-file-element and mw-file-description, so a suggestion would be,

mw-image-border -> mw-file-border
mw-broken-media -> mw-file-broken

There are other classes in the structure that don't quite match this pattern (ex. mw-valign-middle, mw-halign-left, etc) but that's less egregious.