If the browser only knew...but in many cases it doesn't, especially for a fluid width, responsive website. An image may have a near infinite number of potential dimensions depending on the user's viewport.
This theme is discussed here often, but really, this is what HTML was designed for. Load https://thebestmotherfucking.website/ in a browser and scale it at will, it will always look good. The fact that people put a ton of often useless stuff and complain it looks bad in some browser doesn't mean media queries are theonly way.