1.修改镜像
D:\wamp\www\basic2018>composer config -g repo.packagist composer https://packagist.phpcomposer.com
2.安装扩展
D:\wamp\www\basic2018>composer require “yiisoft/yii2-imagine:2.0.0”
参考资料：http://www.yiichina.com/tutorial/903
https://blog.csdn.net/xianglingchuan/article/details/51930960