diff --git a/defaults/main.yml b/defaults/main.yml
index 4ed7fa4..cfc166a 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -70,13 +70,9 @@ nextcloud_preview_folder_name: "preview-generator"
 nextcloud_preview_docker_folder: "/{{ nextcloud_preview_folder_name }}"
 nextcloud_preview_host_folder: "{{ nextcloud_customized_container_src_path }}/{{ nextcloud_preview_folder_name }}"
 nextcloud_preview_first_run_finished_filename: "finished-first-run.keepit"
-nextcloud_preview_squareSizes: "\"64 256 1024 2048\""
-nextcloud_preview_widthSizes: "\"64 256 1024 2048\""
-nextcloud_preview_heightSizes: "\"64 256 1024 2048\""
-nextcloud_preview_preview_max_x: 2048
-nextcloud_preview_preview_max_y: 2048
-nextcloud_preview_system_jpeg_quality: 60
-nextcloud_preview_app_jpeg_quality: "60"
+nextcloud_preview_preview_max_x: null
+nextcloud_preview_preview_max_y: null
+nextcloud_preview_app_jpeg_quality: 80
 
 # nextcloud_container_image_customizations_enabled controls whether a customized Nextcloud image will be built.
 #
diff --git a/tasks/adjust_config.yml b/tasks/adjust_config.yml
index af5e228..66ff419 100644
--- a/tasks/adjust_config.yml
+++ b/tasks/adjust_config.yml
@@ -32,40 +32,20 @@
           cmd: |-
             docker exec --user={{ nextcloud_uid }}:{{ nextcloud_gid }} {{ nextcloud_identifier }}-server php /var/www/html/occ {{ item.appType }} --type={{ item.type }} --value={{ item.value }} -- {{ item.appConfig }} {{ item.configName }}
       with_items:
-        - appType: "config:app:set"
-          appConfig: "previewgenerator"
-          configName: "squareSizes"
-          type: string
-          value: "{{ nextcloud_preview_squareSizes }}"
-        - appType: "config:app:set"
-          appConfig: "previewgenerator"
-          configName: "widthSizes"
-          type: string
-          value: "{{ nextcloud_preview_widthSizes }}"
-        - appType: "config:app:set"
-          appConfig: "previewgenerator"
-          configName: "heightSizes"
-          type: string
-          value: "{{ nextcloud_preview_heightSizes }}"
         - appType: "config:system:set"
           appConfig: ""
           configName: "preview_max_x"
-          type: int
+          type: "string"
           value: "{{ nextcloud_preview_preview_max_x }}"
         - appType: "config:system:set"
           appConfig: ""
           configName: "preview_max_y"
-          type: int
+          type: "string"
           value: "{{ nextcloud_preview_preview_max_y }}"
-        - appType: "config:system:set"
+        - appType: "config:app:set"
           appConfig: ""
           configName: "jpeg_quality"
           type: int
-          value: "{{ nextcloud_preview_system_jpeg_quality }}"
-        - appType: "config:app:set"
-          appConfig: "preview"
-          configName: "jpeg_quality"
-          type: string
           value: "{{ nextcloud_preview_app_jpeg_quality }}"
 
     - name: "Check if {{ nextcloud_preview_first_run_finished_filename }} exists"
diff --git a/tasks/validate_config.yml b/tasks/validate_config.yml
index 8d03b1a..db340f1 100644
--- a/tasks/validate_config.yml
+++ b/tasks/validate_config.yml
@@ -14,6 +14,17 @@
     - nextcloud_database_username
     - nextcloud_database_password
 
+- name: Fail if deprecated Nextcloud settings are still defined
+  ansible.builtin.fail:
+    msg: >-
+      You need to drop setting (`{{ item }}`) as it is not used anymore in the Nextcloud role.
+  when: "item in vars"
+  with_items:
+    - nextcloud_preview_squareSizes
+    - nextcloud_preview_widthSizes
+    - nextcloud_preview_heightSizes
+    - nextcloud_preview_system_jpeg_quality
+
 - name: (Deprecation) Catch and report renamed Nextcloud variables
   ansible.builtin.fail:
     msg: >-