前端实现微信小程序中image的mode=aspectFit保持纵横比缩放图片，使图片的长边能完全显示出来

CSS:

.imgbox{
	display: -webkit-flex;
	width: 30vw;
	height: 30vw;
	display: -moz-flex;
	display: -ms-flex;
	display: -o-flex;
	display: flex;
	align-items: center;
	justify-content: center; 	
}
.imgbox img{
	max-width: 100%;
	max-height: 100%; 
}