title: Why setting max-width: 100% of an image effectively set the maximum to its original width?
body: <p>I know that to make an image responsive but not scaled up beyond its original size, all we have to do is setting max-width: 100%. But I am not sure why that setting works because literally it just tell the browser the image cannot exceed the width of the parent container, instead of the original image size. Could anyone please explain the reasons behind?</p>