diff --git a/README.md b/README.md
index 8b3002b..b43f9e0 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,8 @@ Calls portainer's API and updates the images of all currently active stacks
 ## Usage
 Update configuration file with your portainer access token and the path of portainer compose directory
 
+After restarting all container, it prunes all unused images
+
 You can then simply execute:
 
     python main.py
\ No newline at end of file
diff --git a/main.py b/main.py
index af61b75..930de35 100644
--- a/main.py
+++ b/main.py
@@ -28,3 +28,5 @@ if __name__ == '__main__':
     for s in stack_list:
         if s['Status'] == 1:
             update_stack(s)
+
+    os.system('docker image prune -f')