Since thumbnails are associated with a group of test steps, you can also delete any associated test steps from the Test Steps pane when deleting a thumbnail using the Storyboard. This includes:
All associated automation test steps.
All other types of single-node test steps.
All verification and event logic test steps.
You cannot delete decision and repetition logic test steps associated with the captured image being deleted from the Screen Preview. This ensures the logic is preserved and the visual test plays back correctly. You must manually delete decision and repetition test steps directly from the Test Steps pane.