Which is better for indexing images using CSS or normal image tag? Google’s John Mueller clarified in webmaster hangout at the 20:55 mark that Google Image search does not index or rank images from Cascading Style Sheets. According to him, if you want your images to be ranked in Google Image search, it would be better to use normal image tag with the source attribute pointing at the image.
So do not use this:
For indexing use this:
See the forum discussion at YouTube.