Image native width in jquery

Question

With jQuery, i change the src of an image on click

$(\"#thumb li img\").click(function() {
var newlinkimage = $(this).attr(\"src\");

newlinkimage = newlinkimage         


        

Answer 1

this code always return Zero '0'

    var newimage = new Image();
    newimage.src = 'retouche-hr' + newlinkimage.substring(14,17) + '-a.jpg'; 
    var width = newimage.naturalWidth;
    var height = newimage.naturalHeight;
    alert (width);

WHY ???