Maybe a dumb question, but is there a name for this kind of design element? Zoom, preview or something along those lines?
In German I call this "Detailvergrößerung", so an English equivalent might be "view with detail magnification"; and there is no need for a cute "magnifying glass" to call it that.
Mind that "zoom" can be in or out so is not a precise name. And this element normally is not used for previews but to show more details of actual data or screen objects.