If you are deleting a page with images, you'll see those image versions will be removed when the page is deleted.
Pages - Deleting a page
To delete a page, go to the websites Pages screen and click the x button next to the page you want to delete.
Deleting a page will also remove its automatically created navigation item. Any links made manually can be deleted by following the instructions here.
Deleting a page will not delete the set attached to it, or the images inside the set.
To delete a set once a page has been removed, go into the relevant set and make sure that it is unlocked.In the Delete Set panel, click Delete.