@Mick - that's definitely on the product backlog; it's a feature that is not currently being worked on, but it is one that we would like to implement at some point. There is a potential partial solution for you:

If you click the "settings" link next to your Pogoplug name in the Media Settings Tab you should get a dialog box called "Media Processing Options", with three toggles for each attached drive:
Allow Pogoplug to optimize videos for playback:
Allow Pogoplug to process media meta-data:
Allow Pogoplug to generate thumbnails:
set video and thumbnails to never and the Pogoplug will still scan (and will still put your photos in the right timeline folder), but should no longer process those files, leaving the originals viewable.

The one downside is that we won't generate thumbnails for images or video, so the web interface will only show you a generic icon for your images, but slideshows and view (clicking the magnifying glass) will show your full image.

Hope that's helpful!