Without Attachment Tamer, Apple Mail displays image files in place and usually sends them as embedded images, which in turn are also displayed in place at the recipient's side. With Attachment Tamer's default settings, attachments are displayed as icons and sent as regular attachments. Most email software, in turn, displays such regular attachments as file icons.

If you want to send specific image files as embedded images:

When composing a message, you can right-click (control-click) any image attachment and choose View in Place from its contextual menu. An image displayed in place will be sent as an embedded image.

If you want to send most image files as embedded images:

In the Composing and Sending tab, you can switch Insert attachments to In place (this will not affect incoming mail). All attachments will then be inserted in place. You can still right-click (control-click) individual attachments and choose View as Icon from their contextual menus.