View attachments in Outlook
If you have Mac OS X v10.6 (Snow Leopard) or later, you can see a preview of your message attachments right in Outlook, instead of opening each attachment in a separate application. Attachment previews are available for many file types, such as Microsoft Office documents, photos, and PDF files. You can see each page of a multi-page document, and see a collection of photo attachments as a slide show.
Open the message or view it in the reading pane.
Next to the list of attachments, click Preview or Preview All.
The first attachment is displayed in the preview window.
Use the controls at the bottom of the window to view the attachments. Options include skipping to the next attachment, playing as a slide show, and opening the preview window in full screen.