Sometimes I use the thumbnail to show a detail of the larger image, as in "Lighthouse Island" as the detail would be lost to view otherwise. Actually to me the thumb is an opportunity to show details more than anything. In the "Peace" image the eyes are highlighted, because for the web the smallness of the image causes that detail to recede to much which in print it's fine; so thumb's can lend themselves to different stratgies, not just advertisement. And as to panoramas, the thumb, if one gets the whole image in there pretty much shows nothing.