Verifies if the document is optimized for the Web.
A document that has been optimized for the Web often has a significantly smaller file size. This is achieved by replacing images that occur more than once in the document with pointers to the first instance of these images. Also, the PDF document is restructured to allow page-at-a-time downloading over the Internet: only the page viewed by the user is downloaded, thus avoiding long loading times for larger PDF documents.