You can't. Outlook shows the pictures as they are attached;
in-line; when they were inserted in-line through Insert->
Image.../Picture...
attached; when they were inserted as attachment through Insert-> File...
--
Robert Sparnaaij [MVP-Outlook]
www.howto-outlook.com
Tips of the month:
-FREE tool; QuickMail. Create new Outlook items anywhere from within Windows
-Properly back-up and restore your Outlook data