What if what I want to see is 320 x 400? Or an Appleworks Page
Layout document? Or a regular AWGS document, or one of any other
billion of situations where that isn't going to work?
Once you get the image captured, there is no limit to the ways
you can transform it.
Of course, you won't ever get any more real pixels than the Apple
generates, so I'm not sure what you mean by 320x400.
Any display that can be created on the screen of any Apple II can
be captured (either on a real Apple or on an Apple emulator) and
you can play with it.
If you want more pixels than the screen has, you'll need to use
PostScript.