diff --git a/core/admin/Dockerfile b/core/admin/Dockerfile
index 3d08984..315b2e3 100644
--- a/core/admin/Dockerfile
+++ b/core/admin/Dockerfile
@@ -1,12 +1,16 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN mkdir -p /app
 WORKDIR /app
 
 COPY requirements-prod.txt requirements.txt
 RUN apk add --no-cache openssl curl \
- && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python-dev build-base \
- && pip install -r requirements.txt \
+ && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python3-dev build-base \
+ && pip3 install -r requirements.txt \
  && apk del --no-cache build-dep
 
 COPY mailu ./mailu
diff --git a/core/admin/start.py b/core/admin/start.py
index e8b59ff..59c9768 100755
--- a/core/admin/start.py
+++ b/core/admin/start.py
@@ -1,7 +1,7 @@
-#!/usr/local/bin/python3
+#!/usr/bin/python3
 
 import os
 
-os.system("python manage.py advertise")
-os.system("python manage.py db upgrade")
-os.system("gunicorn -w 4 -b :80 --access-logfile - --error-logfile - --preload mailu:app")
\ No newline at end of file
+os.system("python3 manage.py advertise")
+os.system("python3 manage.py db upgrade")
+os.system("gunicorn -w 4 -b :80 --access-logfile - --error-logfile - --preload mailu:app")
diff --git a/core/dovecot/Dockerfile b/core/dovecot/Dockerfile
index da29756..1d4f7b9 100644
--- a/core/dovecot/Dockerfile
+++ b/core/dovecot/Dockerfile
@@ -1,10 +1,16 @@
 FROM alpine:3.8
-
+# python3 shared with most images
 RUN apk add --no-cache \
-     dovecot dovecot-pigeonhole-plugin dovecot-fts-lucene rspamd-client \
-     bash python3 py3-pip \
- && pip3 install --upgrade pip \
- && pip3 install jinja2 podop tenacity
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
+RUN apk add --no-cache \
+  dovecot dovecot-pigeonhole-plugin dovecot-fts-lucene rspamd-client bash \
+  && pip3 install podop
 
 COPY conf /conf
 COPY start.py /start.py
diff --git a/core/nginx/Dockerfile b/core/nginx/Dockerfile
index 00ecf84..7181487 100644
--- a/core/nginx/Dockerfile
+++ b/core/nginx/Dockerfile
@@ -1,9 +1,13 @@
 FROM alpine:3.8
-
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Image specific layers under this line
 RUN apk add --no-cache certbot nginx nginx-mod-mail openssl curl \
- python py-jinja2 py-requests-toolbelt py-pip \
- && pip install --upgrade pip \
- && pip install idna
+ && pip3 install idna requests
 
 COPY conf /conf
 COPY *.py /
diff --git a/core/nginx/config.py b/core/nginx/config.py
index 33071d0..07b7ea3 100755
--- a/core/nginx/config.py
+++ b/core/nginx/config.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import jinja2
 import os
diff --git a/core/nginx/letsencrypt.py b/core/nginx/letsencrypt.py
index b6044ec..3fe8ea9 100755
--- a/core/nginx/letsencrypt.py
+++ b/core/nginx/letsencrypt.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import time
diff --git a/core/nginx/start.py b/core/nginx/start.py
index b63b64a..7c5fa71 100755
--- a/core/nginx/start.py
+++ b/core/nginx/start.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import subprocess
diff --git a/core/postfix/Dockerfile b/core/postfix/Dockerfile
index e0529e0..ac9c815 100644
--- a/core/postfix/Dockerfile
+++ b/core/postfix/Dockerfile
@@ -1,9 +1,16 @@
 FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
 
 RUN apk add --no-cache postfix postfix-pcre rsyslog \
-    python3 py3-pip \
- && pip3 install --upgrade pip \
- && pip3 install jinja2 podop tenacity
+ && pip3 install podop
 
 COPY conf /conf
 COPY start.py /start.py
diff --git a/optional/clamav/Dockerfile b/optional/clamav/Dockerfile
index fa5f001..b3df2d4 100644
--- a/optional/clamav/Dockerfile
+++ b/optional/clamav/Dockerfile
@@ -1,5 +1,9 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN apk add --no-cache clamav rsyslog wget clamav-libunrar
 
 COPY conf /etc/clamav
diff --git a/optional/clamav/start.py b/optional/clamav/start.py
index e9df3f6..d4701d2 100755
--- a/optional/clamav/start.py
+++ b/optional/clamav/start.py
@@ -1,4 +1,4 @@
-#!/usr/local/bin/python3
+#!/usr/bin/python3
 
 import os
 
@@ -9,4 +9,4 @@ os.system("[ -f /data/main.cvd ] || freshclam")
 os.system("freshclam -d -c 6")
 
 # Run clamav
-os.system("clamd")
\ No newline at end of file
+os.system("clamd")
diff --git a/services/fetchmail/Dockerfile b/services/fetchmail/Dockerfile
index 33f8a7d..52f794d 100644
--- a/services/fetchmail/Dockerfile
+++ b/services/fetchmail/Dockerfile
@@ -1,7 +1,11 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN apk add --no-cache fetchmail ca-certificates \
- && pip install requests
+ && pip3 install requests
 
 COPY fetchmail.py /fetchmail.py
 USER fetchmail
diff --git a/services/fetchmail/fetchmail.py b/services/fetchmail/fetchmail.py
index 8e006f8..9b1bcc4 100755
--- a/services/fetchmail/fetchmail.py
+++ b/services/fetchmail/fetchmail.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/python3
 
 import time
 import os
diff --git a/services/rspamd/Dockerfile b/services/rspamd/Dockerfile
index 76731c9..6d0cb5d 100644
--- a/services/rspamd/Dockerfile
+++ b/services/rspamd/Dockerfile
@@ -1,8 +1,14 @@
 FROM alpine:3.8
-
-RUN apk add --no-cache python py-jinja2 rspamd rspamd-controller rspamd-proxy rspamd-fuzzy ca-certificates py-pip curl\
- && pip install --upgrade pip \
- && pip install tenacity
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Shared layer between rspamd, postfix, dovecot
+RUN pip3 install tenacity
+# Image specific layers under this line
+RUN apk add --no-cache rspamd rspamd-controller rspamd-proxy rspamd-fuzzy ca-certificates curl
 
 RUN mkdir /run/rspamd
 
diff --git a/services/rspamd/start.py b/services/rspamd/start.py
index 015f306..0b3c48a 100755
--- a/services/rspamd/start.py
+++ b/services/rspamd/start.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import jinja2
 import os
diff --git a/services/unbound/Dockerfile b/services/unbound/Dockerfile
index 1b84855..dbf8a3a 100644
--- a/services/unbound/Dockerfile
+++ b/services/unbound/Dockerfile
@@ -1,7 +1,12 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Image specific layers under this line
 RUN apk add --no-cache unbound curl bind-tools \
-  && pip3 install jinja2 \
   && curl -o /etc/unbound/root.hints https://www.internic.net/domain/named.cache \
   && chown root:unbound /etc/unbound \
   && chmod 775 /etc/unbound \
diff --git a/services/unbound/start.py b/services/unbound/start.py
index 82e017f..6f49476 100755
--- a/services/unbound/start.py
+++ b/services/unbound/start.py
@@ -1,4 +1,4 @@
-#!/usr/local/bin/python3
+#!/usr/bin/python3
 
 import jinja2
 import os
diff --git a/webmails/rainloop/Dockerfile b/webmails/rainloop/Dockerfile
index 5d75171..db7403f 100644
--- a/webmails/rainloop/Dockerfile
+++ b/webmails/rainloop/Dockerfile
@@ -1,9 +1,13 @@
 FROM php:7.2-apache
+#Shared layer between rainloop and roundcube
+RUN apt-get update && apt-get install -y \
+  python3 curl \
+  && rm -rf /var/lib/apt/lists
 
 ENV RAINLOOP_URL https://github.com/RainLoop/rainloop-webmail/releases/download/v1.12.1/rainloop-community-1.12.1.zip
 
 RUN apt-get update && apt-get install -y \
-      unzip python3 python3-jinja2 curl \
+      unzip python3-jinja2 \
  && rm -rf /var/www/html/ \
  && mkdir /var/www/html \
  && cd /var/www/html \
diff --git a/webmails/roundcube/Dockerfile b/webmails/roundcube/Dockerfile
index 0c3a0a5..14bee56 100644
--- a/webmails/roundcube/Dockerfile
+++ b/webmails/roundcube/Dockerfile
@@ -1,9 +1,13 @@
 FROM php:7.2-apache
+#Shared layer between rainloop and roundcube
+RUN apt-get update && apt-get install -y \
+  python3 curl \
+  && rm -rf /var/lib/apt/lists
 
 ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz
 
 RUN apt-get update && apt-get install -y \
-      zlib1g-dev curl python3 \
+      zlib1g-dev \
  && docker-php-ext-install zip \
  && echo date.timezone=UTC > /usr/local/etc/php/conf.d/timezone.ini \
  && rm -rf /var/www/html/ \