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You can see it on Gigapan, works on iOS: http://gigapan.com/gigapans/103187

"Size 1.12 Gigapixels"

There was a down-sampling step somewhere between the source image and that Gigapan image.

The image went from 0.121 GP to 1.12 GP, It was not down-sampled, it's the oposite. Maybe to meet Gigapan's minimum 1GP?