If you're going to hide a content image, you're not going to be able to do it by setting display:none. I recommend using a Javascript or server-side based approach instead.
If you want to hide a background image, your best bet is to hide the parent element. If you can't do that, then use a cascade override (like test five above) and set the background-image to none when you want it hidden.
For swapping background images, define them both inside of media queries.
via timkadlec.com
Det här borde väl döda myten en gång för alla? Kan vi inte alla enas om det?