jquery.image.promise.js

var sd = sd || {};
sd.utils = sd.utils || {};

sd.utils.preloadImage = function (url) {
    var deferred = $.Deferred();

    var image = new Image();
    image.src = url;

    image.onload = deferred.resolve;
    image.onerror = deferred.reject;

    if (image.complete) {
        deferred.resolve();
    }   

    return deferred.promise();
};