How can I resize and style images in Outlook for Mac 2011?

Sorry for a negative answer, but Resize image in Outlook for Mac 2011 says :

Sorry, no. You'll need to size your images prior to placing them into your Outlook message.

the Windows version of Outlook has had many years and versions to incorporate features. The Outlook for Mac version is new as of Office 2011 and not everything could be included. Sending feedback to Microsoft will allow them to prioritize development of feature requests from users.

The answer seems to be : Send your feedback and hope for the future.

With Automator that's part of Lion, you can actually create a Service (not an app) so that when you right-click, you have a new menu (ex: “resize pic”) that does the job without having to drag & drop the pics on an annoying icon on the Finder desktop.

In my case, I now use it to resize some chosen pics and add them straight as an attachment to an Outlook 2011 message (as the photo resize feature is badly missing under Outlook).

So I can right click and I have “compress and send via email” when a pic is selected.

It’s clean indeed. Automator is quite powerful in that respect. Should you need more info, please write a comment and I'll elaborate a bit.