var image = new Image();
image.onload = function() {
   // display green arrow
}
image.onerror = function() {
   // display red arrow
}
image.src = 'http://yourserver/test.gif';

编辑：

由于HTML中已有图像，因此onerror事件不仅仅是DOM的HTML的一部分。从理论上讲，如果你不介意无效标记，你可以这样做：

With the images already in the HTML it becomes a bit tricky, because the onerror event is not part of HTML only of the DOM. Theoretically you could do something like this, if you don't mind invalid markup:

<img src="http://yourserver/up_arrow.png" onerror="this.src='down_arrow.png'">