1. A system for conferring interactivity on a sheet having on a surface thereof a pre-printed image containing text, said system comprising a computer system configured for: (i) scanning said pre-printed image on said sheet to form a scanned image; (ii) printing a position-coding pattern on the sheet, said position-coding pattern identifying a plurality of absolute positions and an impression identity for the scanned image; (iii) receiving association data indicating an association between the impression identity, the plurality of absolute positions and the scanned image; (iv) performing Optical Character Recognition (OCR) on the scanned image to convert the text into computer text; (v) generating an input description for said scanned image, said input description describing words of computer text and zones of corresponding text in the scanned image; and (vi) storing a page description comprising said input description and said scanned image, said page description being indexed with said impression identity, wherein said page description is retrievable so as to confer interactivity on the image.