Disable "Loading..." mode while preoading images in Opera

Question

There is crossdomain image, which is loaded for 30 seconds (its 1x1 gif, but server returns if after 30s), via image preloading.

window.onload = function () {
    var img = new Image();
    img.onload = function () { alert('Yey!'); };
    img.onerror = function () { alert('Doh!'); };
    img.src = 'http://cross-domain.com/1x1px.gif';
};

All browsers except Opera's do not show "Loading..." mode. Preloading image via Link, Script, Iframe, CSS - same effect.

How to disable "Loading..." mode while preoading images in Opera?