Re: HD screen captures?
While most people on a forum like this one probably know what OT means, this is not a Star Wars specific forum. As such, you probably should not have used an acronym for "orginal trilogy" and definately should have used the words "Star Wars" in your original post and thread title.
That said, None of the six Star Wars movies have ever been released on Blu-Ray or the now defunct HD-DVD. The only HD version of the original trilogy that I know of was aired on HBO (or one of those many premium channels I don't have). As such, you probably won't be able to find many HD screenshots. You might find some nice production photos that are high rez but not much in the way of still grabs from the movies themselves.