diff --git a/dockerfile-db b/dockerfile-db
index 757aa0b3..4ad66306 100644
--- a/dockerfile-db
+++ b/dockerfile-db
@@ -1,5 +1,5 @@
 # This file is for development work. Not suitable for production.
-FROM mariadb:latest
+FROM mariadb:10.8
 
 # Copy database creation script.
 COPY mysql.sql /docker-entrypoint-initdb.d/
diff --git a/dockerfile-tt b/dockerfile-tt
index 9c79f478..c8edc601 100644
--- a/dockerfile-tt
+++ b/dockerfile-tt
@@ -7,30 +7,25 @@ RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
 # Override with custom settings.
 # COPY config/php_tt.ini $PHP_INI_DIR/conf.d/
 
-# Install mysqli extension.
-RUN docker-php-ext-install mysqli
-
-# Install gd extension.
-RUN apt-get update && apt-get install libpng-dev libfreetype6-dev -y \
- && docker-php-ext-configure gd --with-freetype-dir=/usr/include/ \
- && docker-php-ext-install gd 
-
-# Install ldap extension.
-RUN apt-get install libldap2-dev -y \
-  && docker-php-ext-install ldap
-# TODO: check if ldap works, as the above is missing this step:
-# && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu/ && \
-
-# Cleanup. The intention was to keep image size down.
-# RUN rm -rf /var/lib/apt/lists/*
-#
-# The above does not work. Files are removed, but
-# image files (zipped or not) are not getting smaller. Why?
-
+# Install php extensions.
+RUN apt-get update && apt-get install --no-install-recommends -y \
+  libpng-dev \
+  libfreetype6-dev \
+  libldap2-dev && \
+  rm -rf /var/lib/apt/lists/*
+  
+# Configure php extensions
+RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ \
+ && docker-php-ext-install gd \
+  ldap \
+  mysqli
+ 
 # Copy application source code to /var/www/html/.
 COPY . /var/www/html/
+
 # Create configuration file.
 RUN cp /var/www/html/WEB-INF/config.php.dist /var/www/html/WEB-INF/config.php
+
 # Replace DSN value to something connectable to a Docker container running mariadb.
 RUN sed -i "s|mysqli://root:no@localhost/dbname|mysqli://anuko_user:anuko_pw@anuko_db/timetracker|g" /var/www/html/WEB-INF/config.php
 # Note that db is defined as anuko_db/timetracker where anuko_db is service name and timetracker is db name.