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

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

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 ...

Here is the CSS source code, if you are interested you can look at the code and try to figure out Then here is the HTML code Here you can download those two images Background Image Background-image ...