diff --git a/features/symfony.feature b/features/symfony.feature
index 8dbbc18..e3ea09a 100644
--- a/features/symfony.feature
+++ b/features/symfony.feature
@@ -8,10 +8,10 @@ Feature:
     When I generate the configuration files
     Then the generated "Dockerfile" file should look like:
     """
-    FROM quay.io/continuouspipe/symfony-flex:latest
-    ARG APP_ENV
-    ARG APP_DEBUG
-    ARG APP_SECRET
+    FROM quay.io/continuouspipe/symfony-pack:latest
+    ARG APP_ENV=
+    ARG APP_DEBUG=
+    ARG APP_SECRET=
     COPY . /app/
     WORKDIR /app
     RUN container build
diff --git a/src/ConfigurationGeneration/Symfony/DockerGenerator.php b/src/ConfigurationGeneration/Symfony/DockerGenerator.php
index 59960e9..ef69c01 100644
--- a/src/ConfigurationGeneration/Symfony/DockerGenerator.php
+++ b/src/ConfigurationGeneration/Symfony/DockerGenerator.php
@@ -37,11 +37,11 @@ public function generate(FilesystemInterface $filesystem, array $context) : arra
         }
 
         $dockerFileLines = [
-            'FROM quay.io/continuouspipe/symfony-flex:latest',
+            'FROM quay.io/continuouspipe/symfony-pack:latest',
         ];
 
         foreach ($context['env'] as $key => $value) {
-            $dockerFileLines[] = 'ARG '.$key;
+            $dockerFileLines[] = 'ARG '.$key.'=';
         }
 
         $dockerFileLines[] = 'COPY . /app/';