The only idea I have is using a portable media viewer like say IrfanViewer
the portable version from trusty PortableApps that you can place on the usb stick along with photos), and set it to store its own thumbnails (irfanview has this feature most others have as well). This way the thumbanils will be cached inside its folders on the usb drive.
Then when you want to see your pics/videos you simply fire up the portable irfanview or whatever other program you choose and use it to browse thumbnails and open images/videos instead of standard way.
I know, it's a bit of a hassle, but as Brink said you don't have a better choice with Windows 7