jQuery.preloadImages = function() {
    jQuery.each (arguments,function (e) {
        jQuery("<embed>").attr("src", this);
    });
}

$.preloadImages("/frontend/images/R_tehnolabs_100x60rashlop.swf", "/frontend/images/R_tehnolabs_100x240rashlop1.swf");

$(document).ready(function(){
    $('#rast_1').mouseover(function() {
        $(this).hide();
        $('#rast_2').show();
    })
    $('#rast_2').mouseout(function() {
        $(this).hide('');
        $('#rast_1').show();
    })
})