When we announced Sense/Net Portal Engine TNG, we wanted a fancy picture browser. Since I am an Apple fan, it was a CoverFlow GUI programmed in Flash. If you clicked on a picture folder, the pictures loaded in a fancy way.
As time passed on, we realised that this feature would be nice to have for all Content types in the PFS, so it is now called Preview Mode. Any content in the PFS can have a preview mode icon, which loads when the contenet is listed in a container. So pages, users and folders all have icons in the Preview Mode flash GUI. It is the responsibility of each Content Type to supply the image to Portal Explorer, so you can make your own icon or preview picture for your own content types.
Later, the first two types to have dynamically generated preview icons will be Users and Pages. Users will have photos, if uploaded and pages will have an automatically generated real preview, a shot of the page as it looks like in a browser.
We also have thoughts of using Silverlight / Moonlight instead of Flash.
This is how it looks like for a folder containing images. I hope it will be useful, naturally, eye candy like this is more useful for salespeople and end users. But imagine when you have to find a picture, or a collegue in another department you met once, but can not remember the name... pictures can be useful, and flashy picture browsers can be fun, too. I hope you like it.