Note that pixiv manga viewer got redesigned once again. At this moment the new HTML5 page style doesn't show the "オリジナルサイズ" (original size) links above the page images.

Instead, the original size link is hidden in the page counter at the bottom-right of the screen, e.g. http://i.imgur.com/wSGsi.png

(http://www.pixiv.net/member_illust.php?mode=manga&illust_id=16309793)

Thank you 4get was ust going to ask about it

Yes, thank you, 4get!