在javascript中定义.style.height不能使用canvas图像

Question

我有以下代码，由于某种原因，我无法弄清楚，它不起作用。我试过了两个：     image.style.height = '10px';和image.height = '10px';

var canvas = document.getElementById('canvas');
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
var image = new Image();
image.src = "http://pngimg.com/upload/horse_PNG2523.png";
image.style.height = '10px';
image.style.width = '20px';