When it comes to preloading the images of your website so that you can give your visitors with slower connections a bit of a break when it comes to the wait, there are three main methods that work the best. These are:
2 – Use CSS. CSS can be used to hide images that are to be preloaded. Since browsers load web pages from the top to the bottom, you need only to load the rollover images at the top of the page. So that the visitors don’t see the images right away, you need only hide them with the right div. You won’t need any alt tags at all, but you will want to tweak the height and width to get better speed.