有几种方法可以做到这一点:

There is a few ways to do that:

使用ajax:

$.ajax({
    url: "image.jpg",
    type: "HEAD",
    error: function () { alert("no image"); }
});

使用javascript图像对象:

Using the javascript image object:

var image = new Image(); 
image.src = "image.jpg";
if (image.width == 0) {
  alert("no image");
}