How do you guys like to preload your bigger images to be used later?

A lot of the articles I keep finding are dated 1999 to 2000 :[

It's been a while since I did any image pre-loading With connection speeds getting faster it becomes less of an issue. I think the last time I did it we had the images written to a hidden <span> tag on the page (with JS) after everything else had loaded. They weren't particularly big images though, they were background images for a contact form that appears when a button is clicked.

I'd personally just use JS.

var i = new Image();
i.src = 'blah.jpg';

That is the method in my JS book