You are applying background-image property to an img element. That is not how you should do it. And also in your context if img hides, its background will also hide, they are not separate elements.
So to hide one of the element they should be separated and one should be placed on top of another.
You an also check the files of WildMusic example. In the tutorial I’ve mentioned that the top image is an overlay. So if you want to get more idea check the codes.