Anyway, it could be said, it´s not a far-fetched or wrong thing. Since, short is to talk about horizontal lenght (as opposite to long). <->
Anyway, the opposite long vs short is more seen used when talking about time, books, words/sentences, hair, and legs.
When talking about vertical lenght, it would be "short" as opposed to "tall".
So, when we say small we are talking a 'big" room vs a "small" room, we are indeed talking about general size, or if you wish, thinking more or less in 3D.
So, big would be spacious and small would be cramped/less spacious etc.