Aperio Technologies has made "the world's first terapixel image". However, it actually consists of one picture copied 225 times—that off cancerous breast tissue. As a digital pathology imaging company, one could interpret the image as Aperio flexing their digital muscle while raising awareness for an (obviously) important issue.
The picture is a 144GB .tif (using JPEG compression). And you can zoom online using the link below. Without one big image to play with, the scale of one trillion pixels is still tough to grasp. Let's just dub it a lot of pixel and call it a day.