As in take a snapshot/image of the video? By default VLC's snapshot button saves a *.png file of the videos original size (you could then scale that up in an image editor to be "HD" or whatever size you like - the scaled result will be similar(/better) to what VLC output anyway).
VLC can resize snapshots (see in the preferences) however I'm not sure that works in VLC 0.9.8a.
If you are using Windows then pressing "Prt Scr" probably won't display the video when pasted. Change the output module to e.g. OpenGL and then Prt Scr should work - so you could do that in fullscreen more, for example. See here for how to change the video output module:
http://wiki.videolan.org/WindowsFAQ#Why ... _output.3F
Arite.