Img versus pure CSS.

Question

How long does it take to load ?
I guess CSS wins but how many percent faster ?

Answer 1

These differences will very by machine and other conditions. It also depends a lot on the size of your image. A vector image will be similar to CSS, because they both draw the image with math. A large rastorized image will take a long time to download, because it is a massive list of pixels--basically, as long as it takes to download however many mbs of data.

So large jpg will be slow.
Svg will be fast.