Google says images styled with CSS won’t be indexed in Image Search, advising developers to use HTML tags for important visuals. CSS background images aren’t indexed by Google Image Search.

Add a short CSS class to an HTML Web page to use animated and stationary GIF images as the page's background.

How to Make an Image Footer Stay Down in CSS. Footers are a great place to add extra content to a website without letting it get in the way of the rest of the page. Social networking badges ...

John said this also back in January 2018 when he said Google Image search does not index and rank images from CSS background code.

Google's John Mueller said this morning in a webmaster hangout at the 20:55 mark that Google Image search does not index and rank images from CSS background code. He said if you want your images ...