# 使用镜像

在之前的介绍中，我们知道镜像是 Docker 的三大组件之一。

Docker 运行容器前需要本地存在对应的镜像，如果本地不存在该镜像，Docker 会从镜像仓库下载该镜像。

本章将介绍更多关于镜像的内容，包括：

* 从仓库获取镜像；
* 管理本地主机上的镜像；
* 介绍镜像实现的基本原理。


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