$(window).bind('resize', function() {
	resizeMainImage();
});

$(document).ready(function(){	
	if ($("#mainImg img")[0].complete || $("#mainImg img")[0].readyState === 4) {
	    // do on load complete	
		resizeMainImage();
	} else {
	    $("#mainImg img").bind('load', function(){	
	        // do on load complete	
			resizeMainImage();
	    });
	}
});

function resizeMainImage() {
	$("#mainImg img").css("left", -($("#mainImg img").width() - $("#mainImg").width()) / 2);
}