naturalWidth and naturalHeight
var img = document.createElement("img");
img.onload = function (event)
{
console.log("natural:", img.naturalWidth, img.naturalHeight);
console.log("width,height:", img.width, img.height);
console.log("offsetW,offsetH:", img.offsetWidth, img.offsetHeight);
}
img.src = "image.jpg";
document.body.appendChild(img);
// css for tests
img { width:50%;height:50%; }