As a best practice, we always recommend using PoliteMail > Add Image.
However, if you paste images into your email, or use Outlook’s Insert picture command, Outlook will place the images into your email as file attachments.
When you send to yourself or other Outlook users within your company, you may not see the attachments – but your recipients may see them once you send outside of your network (e.g. to a Gmail account).
Outlook will also keep a temporary copy of deleted or replaced images within the email while editing. However, when you save the email as a PoliteMail Template, all those attachments are included. So when you reload the template and send it you it may attach some images which are not in use within the email.