[zupa-hu]

Except the viewer is loosing context. I'd go the opposite direction and show the entire screen. (Of course shrink your screen size to be just right.) If you want, maybe zoom in later once you have given context. I don't know otherwise if this runs in the browser or if it is a standalone app.

[7Z7]

I'm pretty sure you are both talking about the same thing. The used phrase "zoom in and crop" implies starting with context, zooming in, and showing the close-up feature. Otherwise s/he could have just said "crop".