Don't know about Outlook Professional, I use Outlook 2000, part of Office 2K. When I receive attatchments, Outlook launches the appropriate program to veiw the file. In my case, with jpegs, Paintshop Pro. If you are using Outlook as part of the Office suite you should be able to install MS Photo Editor, a basic pix programme. When it is installed it registers itself as your default viewer for certain file types, one of which will be jpegs.
If the cat trys to sit on the keyboard one more time so help me I will strangle it.