Screen captures from Hi-Def Original Trilogy?

[Jedilaw]

Hello all,

The Original Trilogy has been broadcast in HD on Cinemax and on HBO. I have it on my mother-in-law's HD DVR, but cannot extract the files for backup, and cannot take screen captures.

Would anyone have any screen captures from Empire and/or Jedi? Specifically, I am looking for hi-def shots of the Star Destroyer, which I am modeling in CG.

I'm not looking for any kind of "download the movies here" type stuff, as that would violate copyright. I am merely interested in some still screen grabs, to use as reference material.

Thanks in advance,

Jedilaw