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

This value tells browsers to make the image repeat across the page and down the page to produce a grid effect. Delete that statement if you don't want your GIF to create a tiled background.

How Do I Create Multiple Fixed Backgrounds in My CSS File?. Cascading Style Sheets (CSS) level 3, also known as CSS3, introduces multiple background images support.

Ryan Boudreaux includes all the code snippets you'll need in this demo of how to create an image hover-preview effect using HTML, CSS, and JavaScript.