getImg() {
	this.imageReady(imgArr).then(() => {
		//do something
	})
}
imageReady(pics) {
    const picsAll = pics.map(imgurl => new Promise((resolve, reject) => {
    	// 小程序判斷多張圖片是否加載完成方法
        wx.getImageInfo({
            src: imgurl,
            success: function() {
                resolve(imgurl);
            },
            fail: function() {
            	reject(new Error('image load error'));
            }
        });
        // H5 判斷圖片是否加載完成方法
        // const img = new Image();
        // img.src = imgurl;
        // img.onload = () => resolve(imgurl);
        // img.onerror = () => reject(new Error('image load error'));
    }));
    return Promise.all(picsAll).then(() => {
    }).catch((e) => {
    });
},