在使用Docker时我想pull远端仓库的CentOS 6的镜像，我是这样操作的
docker search centos
返回的结果：
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
centos The official build of CentOS. 3160 [OK]
jdeathe/centos-ssh CentOS-6 6.8 x86_64 / CentOS-7 7.3.1611 x8... 61 [OK]
nimmis/java-centos This is docker images of CentOS 7 with dif... 23 [OK]
consol/centos-xfce-vnc Centos container with "headless" VNC sessi... 22 [OK]
gluster/gluster-centos Official GlusterFS Image [ CentOS-7 + Glu... 18 [OK]
million12/centos-supervisor Base CentOS-7 with supervisord launcher, h... 13 [OK]
torusware/speedus-centos Always updated official CentOS docker imag... 8 [OK]
egyptianbman/docker-centos-nginx-php A simple and highly configurable docker co... 6 [OK]
nathonfowlie/centos-jre Latest CentOS image with the JRE pre-insta... 5 [OK]
centos/mariadb55-centos7 4 [OK]
consol/sakuli-centos-xfce Sakuli JavaScript based end-2-end testing ... 3 [OK]
harisekhon/centos-java Java on CentOS (OpenJDK, tags jre/jdk7-8) 2 [OK]
harisekhon/centos-scala Scala + CentOS (OpenJDK tags 2.10-jre7 - 2... 2 [OK]
centos/redis Redis built for CentOS 2 [OK]
blacklabelops/centos CentOS Base Image! Built and Updates Daily! 1 [OK]
darksheer/centos Base Centos Image -- Updated hourly 1 [OK]
freenas/centos Simple CentOS Linux interactive container 1 [OK]
timhughes/centos Centos with systemd installed and running 1 [OK]
smartentry/centos centos with smartentry 0 [OK]
januswel/centos yum update-ed CentOS image 0 [OK]
termbox/centos CentOS 0 [OK]
otagoweb/centos Apache (with PHP7), built on CentOS 7 0 [OK]
repositoryjp/centos Docker Image for CentOS. 0 [OK]
vcatechnology/centos A CentOS Image which is updated daily 0 [OK]
labengine/centos Centos image base 0 [OK]
docker pull centos然后下载下来的时最新的CentOS镜像，为版本7，我想下载版本为6的CentOS镜像，我在
search的时候如何查看到tag，就以这里为例，我想下载官方的CentOS6的镜像，我想官方应该有提供CentOS6的镜像，我不知道怎么查看
{ dir } » docker search --help
Usage: docker search [OPTIONS] TERM
Search the Docker Hub for images
Options:
-f, --filter filter Filter output based on conditions provided
--help Print usage
--limit int Max number of search results (default 25)
--no-trunc Don't truncate output查看了
docker search的选项，没有发现与tag相关的
这种问题大家是怎么解决的?
