I think `width: null` is confusing because the default behaviour (`width: undefined`) resizes the image according to the browser's viewport, I'd expect the same behaviour with null.

Plus, I think we have to be careful about naming this something that associates it strictly with `width` because logically this disables resizing all-together (incl. other properties that control resizing today and in the future: `maxHeight`, etc.)

How about something like `resize` or `passthroughResize`?