preloadImagesCSS.js

jQuery.preloadImagesCSS = function() {

    var allImgs = [],
        k = 0,
        sheets = document.styleSheets;

    for (var i = 0; i<sheets .length; i++) {
        var cssPile = '',
            csshref = (sheets[i].href) ? sheets[i].href : 'window.location.href';

        if (document.styleSheets[i].cssRules) {
            var thisSheetRules = document.styleSheets[i].cssRules;
            for (var j = 0; j<thisSheetRules.length; j++) {
                cssPile+= thisSheetRules[j].cssText;
            }
        } else {
            cssPile += document.styleSheets[i].cssText;
        }

        var imgUrls = cssPile.match(/[^\(]+\.(gif|jpg|jpeg|png)/g);

        if (imgUrls !== null && imgUrls.length > 0 && imgUrls !== '') {
            var images = jQuery.makeArray(imgUrls);
            jQuery(images).each(function(index, image){
                allImgs[k] = new Image();
                allImgs[k].src = image;
                k++;
            });
        }
    }
    return allImgs;
};