diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 97110ecd..388cc49a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,50 +10,23 @@ variables:
 # Debian Buster
 py37-django22:
   stage: test
-  image: debian:buster-backports
-  before_script:
-    - >
-        apt-get update &&
-        apt-get install --no-install-recommends -t buster-backports -y
-        python3-django python3-django-crispy-forms
-        python3-django-extensions python3-django-filters python3-django-polymorphic
-        python3-djangorestframework python3-django-oauth-toolkit python3-psycopg2 python3-pil
-        python3-babel python3-lockfile python3-pip python3-phonenumbers python3-memcache
-        python3-bs4 python3-setuptools tox texlive-xetex
+  image: otthorn/nk20_ci_37
   script: tox -e py37-django22
 
 # Ubuntu 20.04
 py38-django22:
   stage: test
+  image: otthorn/nk20_ci_37
   image: ubuntu:20.04
-  before_script:
-    # Fix tzdata prompt
-    - ln -sf /usr/share/zoneinfo/Europe/Paris /etc/localtime && echo Europe/Paris > /etc/timezone
-    - >
-        apt-get update &&
-        apt-get install --no-install-recommends -y
-        python3-django python3-django-crispy-forms
-        python3-django-extensions python3-django-filters python3-django-polymorphic
-        python3-djangorestframework python3-django-oauth-toolkit python3-psycopg2 python3-pil
-        python3-babel python3-lockfile python3-pip python3-phonenumbers python3-memcache
-        python3-bs4 python3-setuptools tox texlive-xetex
   script: tox -e py38-django22
 
 # Debian Bullseye
 py39-django22:
   stage: test
-  image: debian:bullseye
-  before_script:
-    - >
-        apt-get update &&
-        apt-get install --no-install-recommends -y
-        python3-django python3-django-crispy-forms
-        python3-django-extensions python3-django-filters python3-django-polymorphic
-        python3-djangorestframework python3-django-oauth-toolkit python3-psycopg2 python3-pil
-        python3-babel python3-lockfile python3-pip python3-phonenumbers python3-memcache
-        python3-bs4 python3-setuptools tox texlive-xetex
+  image: otthorn/nk20_ci_37
   script: tox -e py39-django22
 
+# Tox linter
 linters:
   stage: quality-assurance
   image: debian:buster-backports