Comment by tshaddox

Yeah, this isn't really that complicated. It's just colloquial usage, not rigorous dimensional analysis. Roughly no one is actually confused by either usage ("1920 by 1080" or "12 megapixels").

It's nearly identical to North American usage of "block" (as in "city block"). Merriam Webster lists these two definitions (among many others):

> 6 a (1): a usually rectangular space (as in a city) enclosed by streets and occupied by or intended for buildings

> 6 a (2): the distance along one of the sides of such a block