在Dockerfile中如何给镜像命名（tag）

# PHP
FROM php:7.4.25-fpm
EXPOSE 9000
VOLUME ["~/nginx/www", "/www"]
# 安装mysqli
RUN /usr/local/bin/docker-php-ext-install mysqli

# Nginx
FROM nginx:latest
EXPOSE 80 443
VOLUME ["~/nginx/www", "/usr/share/nginx/html"]
VOLUME ["~/nginx/conf.d", "/usr/share/nginx/conf.d"]