.size()方法报错：Image uninitialized about node-images HOT 5 CLOSED

ERROR: ../src/Image.cc:390 Image uninitialized. 

 Error: ../src/Image.cc:390 Image uninitialized.

var images = require('images');
var img = images('a.png');

// 等比缩放
img.size(img.width() * 180 / img.height(), 180);

if (img.width() < 300) {
    return ;
}

if (img.height() < 180) {
    return ;
}

var x = (img.width() - 300) / 2;
var y = (img.height() - 215) / 2;
return images(img, x, y, 300, 180).save('b.png');

ERROR: ../src/Image.cc:390 Image uninitialized. 

 Error: ../src/Image.cc:390 Image uninitialized.