> tl;dr css hover selectors that change the background image don't actually cause the browser to GET the specified background image until you hover over it Thi

> tl;dr css hover selectors that change the background image don't actually cause the browser to GET the specified background image until you hover over it This specific page uses :active, not :hover, so it is really no different from a web form, that performs web request each time you press a submit button. It just does not reload a page.