Trouble with images size

Docker Engine Compose
1

Hi everybody,

I have a problem with the virtual size of my docker machine. This is some informations :

My environment :

Mac OSX Hight Sierra, docker-machine (with virtual-box) And docker-compose

My docker machine :

NAME   ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER        ERRORS
dev    *        virtualbox   Running   tcp://192.168.99.100:2376           v17.10.0-ce

My docker images :

CONTAINER ID        IMAGE                                        COMMAND                  CREATED             STATUS              PORTS                     NAMES                      SIZE
e1f482f9d7de        www_app                                      "/run.sh"                2 days ago          Up 2 days           80/tcp                    www_app_1                  142kB (virtual 563MB)
593f57818634        eu.gcr.io/registry/www:db-full            "docker-entrypoint.s…"   5 days ago          Up 2 days           0.0.0.0:5431->5432/tcp    www_postgres_1             42.8GB (virtual 87.1GB)
524a6ae68e25        eu.gcr.io/registry/redis:cluster          "/docker-entrypoint.…"   5 days ago          Up 2 days           6379/tcp, 7000-7005/tcp   www_redis_cluster_1        64.4kB (virtual 547MB)

My docker compose file :

version: '2.1'
services:
  # A generic container with apache server ,php 7 and psql support
  app_base:
    build: app/Resources/docker/app-base
    volumes:
      - .:/app/www
      - ~/.ssh:/home/www-data/.ssh
      - $COMPOSER_HOME:/home/www-data/.composer
    environment:
      USER_ID: $VOLUME_USER_ID
    entrypoint: /run.sh

  # The development database
  postgres:
    image: eu.gcr.io/registry/www:db-full
    ports:
      - 5431:5432

  # The development web instance
  app:
    extends:
      service: app_base
    links:
      - postgres
      - redis_cluster
    networks:
      default: ~
      mynetwork:
        aliases:
          - dev.test-my-host.com
    environment:
      - VIRTUAL_HOST=dev.*

  # The compose entrypoint for every commands on the project (DB rebuild, cache clear, ...)
  toolbox:
    extends:
      service: app_base
    entrypoint: /toolbox.sh
    links:
      - postgres
      - redis_cluster

  # The development Redis Cache
  redis_cluster:
    image: eu.gcr.io/registry/redis:cluster

networks:
  mynetwork:
    external:
      name: mynetwork

This is my problem : I have a database witch is rebuild all night (because took a lot of time) and push to the google cloud registry. This container get 42,8GB on the dick space. But the virtual size get the double ! I know that the virtual size is the total size of all containers using my container. But how can I change my docker compose to use the physic container ? (This container is used one time).

Thank you !!