Since it looks like the functionality you are expecting is not available in Windows Vista, you can use VLC to open the camera as a "Capture Device" and then take snapshots using VLC. The VLC FAQ explains tells us that to take a snapshot:
How can I take screenshots?
To take a snapshot of the video
displayed by VLC, you just need to
press the pre-defined snapshot hotkey:
- Windows / Linux / Unix: Ctrl+Alt+S
- Mac OS X: Command+Alt+s
To change it, go to Preferences ->
Interface -> Hotkeys settings, check
Advanced options, and set Take video
snapshot.
You can also take a snaphot via the
menu Video -> Snapshot.
To change the snapshot format or
directory, go to Preferences -> Video.
Where are my screenshots?
If you haven't changed the snapshot
directory in your preferences, your
screenshots should go to:
- Windows:
My Documents\My Pictures\
- Linux / Unix:
$(HOME)/.vlc/
- Mac OS X:
Desktop/
To change it, go to Preferences ->
Video -> Video snapshot directory.